2001 Gr Cherokee Jeep Laredo-reverse gear problems

[skthenonmechanic]

Hello Jeep People!
need some guidance please.
Have 2001 Jeep grand cherokee Laredo.
Not driven in 2.5 years>reverse gear broke down.
aprox 183k miles; sitting in driveway>Atlanta climate.
Gas tank>aprox 3 gallons (under quarter of tank)

looking to sell for $1200 as is...is this realistic?
battery has been recharged>not yet started up due to gasoline concerns>old gas>is it compromised?
need to drain?
Did the sniff test>no odd odor detected.

Research thus far is>drain or dilute with fresh gas.

Thoughts/suggestions from the experts.
Thanks group; appreciate your feedback!