We bought our 06 Dolphin as 1 year old "new" unit with around 300 miles on the clock. Got full warranty on everything. The batteries tanked after 3 years of use, not bad considering the abuse they get on a lot. The tires, Michelins, started cracking after 6 years of owning an Michelin adjusted them crediting almost the full price equivalent of 1 tire of the 6.
Make sure no excess wear and run it through the bluebook, we paid out the door with fancy wax job, scotchgard interior, and 7 year extended warranty $1000 below bluebook for 1 year old used coach.