Beef bone knuckles, or even the full femur. You can find these at a butcher or any decent pet store. About $15 but boy do they help.

Another huge hit that lasts a while is Hemilayian Yak bones. These are literally dried cheese sticks that are as hard as a bone. My dogs LOVE them.

https://www.amazon.com/Himalayan-Quality-Natural-Odorless-Enjoying/dp/B07JDYXQ87/ref=sr_1_1_sspa?crid=35D3S56CX7FQ1&keywords=yak+bones&qid=1564086985&s=gateway&sprefix=yak+bone%2Caps%2C486&sr=8-1-spons&psc=1

As someone with a Tibetan Mastiff I can confirm most of these. For example, #2 for their original purpose of guarding against wolves, leopards, etc. One additional detail is they're one of the first dogs to utilize a spiked collar, to protect their necks against them.

7, can confirm. My pup doesn't want to come inside since its gotten below 40 degrees F. He loves it so much.

8, they're actually better watch dogs than guard dogs. They'll use their bark and size to intimidate any potential intruders. Their bite can be strong, but it won't be nearly the same as say a German Shepard.

If anyone is interested, I recommend this book (recommend kindle version just because of the price) since it covers not just owner care, but history and expectations too.

http://www.amazon.com/Tibetan-Mastiff-Comprehensive-Owners-Guide-ebook/dp/B008BGDI7M/ref=sr_1_2?ie=UTF8&qid=1417629856&sr=8-2&keywords=tibetan+mastiff

Our vet, who raises mastiffs, suggested this to us:

Holistic Select Natural Dry Dog Food

We haven't had any problems and our Meatball loves it to death.

Although, on Saturday, he tried to convince me he loved used cat litter, too, so take that part with a grain of salt.

This is the one I bought: Ideal Pet Products Ruff-Weather Pet Door with Telescoping Frame, Super Large, 15" x 23.5" Flap Size https://www.amazon.com/dp/B0017JTVGC/ref=cm_sw_r_cp_apap_gvyvZ8vQTjgY7

I got the biggest one of these: http://www.amazon.com/Sealy-Dog-Bed-Technology-Large/dp/B00G3D4TPU

Coconut likes it. one of her other beds is just the cushion from a papasan chair.

Whatever you get make sure it has a removable cover for easy cleaning.

I am so sorry to hear this. I lost my first girl to osteosarcoma 5 years ago. Penny was my souls dog and she was diagnosed when she was 5. How old is your beautiful girl?
We found it quite early and initially did radiation and chemo. We had to amputate after about 1 month because she broke the leg (not uncommon with osteosarcoma but awful.) In retrospect I would go straight to amputation because she did so great after the leg was gone. It’s a really painful cancer, and about 2 weeks after the surgery she was running around like her old self because that pain was gone. 4 months after her initial diagnosis she tore the CCL in her remaining back leg. At the time, there was no evidence of mets but both the oncologist and the surgeon who did her amputation recommended we put her to sleep because she likely wouldn’t recover from the CCL surgery. I was completely devastated.
If I had to do it all over, the chemo and amputation were definitely worth it. She was an active, playful girl and truly thrived post amputation. I’m happy she had a few more months where she could enjoy herself.
I highly recommend this book. It really helped with our decision to say goodbye, and was a great primer on all things canine cancer.
I am so sorry you both have been dealt this shitty hand. I hate for any dog owner to have to go through it

We order our dog food from Amazon. I know you don't want to waste time to have it shipped, but it's significantly cheaper online than at Petco. It's called Taste of the Wild. It's grain-free, and that helps with my bulldog's gas problems and its quality keeps the size of poops from being so big. We typically buy the salmon version, but here's the puppy formula which is also grain free.

Just curious why the pronged choker? Is he particularly aggressive?
My english is sweet enough that I've never needed anything other than a gentle leader during training.

Bella gets 2.5 cups twice a day of Purina Pro Plan Sensitive Skin and Stomach (http://www.amazon.com/dp/B003R0LLIU/ref=pe_385040_30332190_TE_dp_1). She used to get Wellness large breed food but started refusing to eat it. This one she likes! Make sure you slowly transition from one food to the other to prevent an upset stomach.

Also, if she's really itchy, you should ask your vet about giving her benadryl or something like that. We give Bella 100mg twice a day and it has done wonders for her itchy skin!

We got the Armarkat Pet Bed Mat https://www.amazon.com/dp/B003BYQ092/ref=cm_sw_r_other_apa_zs4rxb1TGT5SE. 6 months and still in good shape

This is the one we have.
Squishy Face Studio Flirt Pole V2 Dog Exercise Toy Bundle with 2 Fleece Lures and Fleece Tug, 36-Inch https://www.amazon.com/dp/B00HFFX3VQ/ref=cm_sw_r_udp_awd_0oCZtb12RX98H8QB
The pole is very sturdy and stands up to our Presa very well

I feed mine Taste of The Wild he seems to do really well on it and when I tried other dog foods he refused to eat.

http://www.amazon.com/Taste-Wild-Prairie-Formula-30-Pound/dp/B000W5SLB8

I used the Petmate sky kennel XL.

https://www.amazon.com/Petmate-Kennel-Portable-Travel-Included/dp/B003E6YYYK

Is your final destination Honolulu or one of the other islands?

https://www.amazon.com/gp/aw/d/B00KSIAUV8/ref=ya_aw_od_pi?ie=UTF8&psc=1

https://www.amazon.com/gp/aw/d/B007NIDPZ4/ref=mp_s_a_1_3?ie=UTF8&qid=1521338933&sr=8-3&keywords=extra+large+soft+dog+crate&dpPl=1&dpID=51X4BdsrbmL&ref=plSrch

This is the one we got. Caution, it’s ridiculously big. Caution number two, usually he sleeps on the couch.

By "kennel" you are referring to a portable crate, correct? I just want to make sure I'm not misunderstanding, or that you aren't asking for a true built-in kennel solution.

Assuming you mean a crate-type kennel, I'd suggest getting one big enough for when your puppy is full grown. At that point you want it to be big enough for them to stand up, turn around, lie down, etc. comfortably. This might mean something a little larger if it is an English Mastiff than if it is a slightly smaller Mastiff variation.

Get a crate big enough for the final height/weight of your puppy to do that. Then, get a divider for the crate if it doesn't come with one. The crate we started with had a divider wall that came with it. When our Bullmastiff was a puppy, we moved this divider as he got bigger, then eventually removed it completely. The idea is to give them enough room to get up, turn around, and lie down, but not enough room to have an accident in the crate without it being in their space.

Here is an example of a crate that might work, and a divider that could go in it:

https://www.amazon.com/Midwest-Solution-Ginormous-Double-Crate/dp/B005VVWBVY/ref=sr_1_1?ie=UTF8&qid=1505914785&sr=8-1&keywords=giant+dog+crates

https://www.amazon.com/MidWest-Homes-Pets-Divider-Models/dp/B00CMHA2ZM/ref=pd_sim_199_2?_encoding=UTF8&psc=1&refRID=3X05321SY28EZQ6CMRDP&dpID=41uuZ0MnB2L&preST=_SY300_QL70_&dpSrc=detail

There are cheaper options, or depending on the breed you might go with a slightly different sized crate, but that gives you a general idea.