I sold a ZR a little over a year ago for around $300-350. It was in top condition only a few small issues with side art. Great looking game! But it is a niche title with only a small fan base, and it weighs 450lbs and takes up a lot of space.
Simpsons Bowling- I think we have about 4 or 5 of those at the shop, they are pretty common. The problem with those is the HDD goes bad on them so finding a working one is usually a challenge. Fitted with a solid state drive it should be worth $300-400 i would imagine on a players quality cabinet.