I am assembling something similar, but less for the trail and more for the road. We can ride on the roads here and there are hundreds of miles of pavement and gravel to cover, but we ride alone and there isn't cell coverage everywhere, so having stuff like this with you is just as important.
When I bought my 07 ranger 700 efi, I went through and tested every Torx screw I could find, as well as every external hex nut/bolt. In the end I found I needed only 3 sizes of Torx and I think 6 sockets for everything from taking the valve cover off to swapping a tire. I bought copies of all those and a new small tool box, and started the kit along with extensions and ratchet handles.
Other than the tools, this is what I carry:
- Spare TPS (bought a used one on ebay, tested it)
- The means/tools to swap and calibrate a TPS
- Idle adjustment tool
- Some spare wire
- Butane powered soldering iron which is also a torch for shrink wrap (the only acceptable way to fix wiring that could be exposed to moister IMO)
- All the stuff needed to solder (solder, flux, shrink wrap, de-soldering wick)
- Electrical tape
- Spare tire
- Extra oil
- Extra antifeeze/distilled water if it's warm there
- Portable jump pack (one of the small ones) for dead battery
- Extra key, and/or the means to bypass the ignition switch if needed
- Drive belt (new oem spare) and the means to change it
- A printed wire diagram from the manual
Because it took me no more than 30 minutes and basic tools to swap the fuel pump, I plan to carry a spare cheap/aftermarket of that as well. Really I poked around for problems that people seem to have repetitively, and tried my best to plan a roadside fix for each of them. This is my first ranger and we have only had it a little over a week so I'm sure we will be adding to it.
This seems like a lot, but it's all small stuff and everything fits easily in the under-seat storage and leaves tons of room for other stuff yet, so I think it's worth it. And when stuff breaks I can have the parts right away even if it doesn't stand me.
To answer your last question; I'm not sure, however, I looked at the manual and it describes the front/rear as diffs, so unless the diff is locked I would expect it to deal with different tire sizes (or track vs. tire sizes) without issue. This is my first Polaris, but on Honda ATV's I've ran different sized left/rights in emergencies before and those diffs had zero issue with it.