Ive done the neglected truck thing. Valvoline Restore and Protect and 4,000mile oci. Probably want a big ole oversized rock catching wix xp oil filter.
You may want to change the oil and filter after your first road trip.
I also take care of( cause my aunt asks me to)his Honda Recon 250, two zero turn lawnmowers, and Honda 90 outboard, all neglected.
I might just start dumping 15W40 in all of it once a year and call it good.