Can I rent a motorcycle to use there, sort of like the kart tracks?

No you can not

Not from the racetrack itself, to my knowledge. I believe there might be some track day organizations that run events at Summit that might offer something like that. Most rentals that I'm aware of occur in a "school" setting, not just an open track day.

Not that I've ever seen

Nope...

Karts aren't there any more to rent. The kart club from Woodbridge va runs there. Check there web site out. Never heard of tenting a bike there.

Not that I'm aware of. Maybe check with Chris white or Roger lyle with motorcycle excitement