Best Practices to Restore Older Xplorer 4x4s

Hello Everyone!

Why:
Please help me and others, by contributing to a useful "best practices in restoring an old Polaris Xplorer" thread. Hopefully, we can generate a good list to help myself and the whole community. I can synthesize a checklist including consensus agreements.

Background:
I am attempting to revive a 1998 Polaris 300 Xplorer 4×4 that has been stored in a open-door huge machine shed/pole barn for 10yrs, due to a suspected reverse over-ride switch problem. I get the ATV for free if I can get it running. I tend to believe there are potential problems that could be avoided by pre-starting maintenence…anyone agree? Do we have a related thread already on the topic (I couldn’t find one easily)?

So Far:
only preliminary tried to start with pull-starter. Needs new battery. Didn’t start.

Planned:
Replacespark plug (needed or not, examine old one)
Replace old gas & replace with fresh
replace fuel filter
Replace Oil change & filter

Clean battery cables
Clean air filter
Clean battery cables
Clean and visually inspect overall machine, remove plastics to facilitate access
Obtain new battery (jumpstart in meantime with car-sized 12-volt)

Help:
transmission flush?
carburetor maintenance?

….Then try starting via car-sized battery and test functionality and find additional problems, determine if further work worth the cost to continue restoration.