Hi. It's hard to say what category the Telstar is in, but I think it's a B+ or larger.
This one was for sale, and was put in the ad as a small C, but it's 23 feet long (Sprinter sized)
http://www.rvclearinghouse.com/index/li ... ge6544.htm
or this one as a B+ but it's 27 feet long which makes it pretty much a C (to me, anyway).
http://www.rvt.com/rvdetail4537040.htm
I think a true class B is loosely defined as a van conversion, meaning the majority of the original
van chassis and body and mechanicals remain intact, and the various RV functional systems are added.
Anyway, welcome, sorry to hear about the tires, hope you had a reliable ERS company.
I'd imagine the gas mileage will get better once you get a few road trips under your belt.
Takes a bit of trial and error to get the hang of coaxing an extra mile or two out of a gallon.
Correct tire pressure, clean oil/filter, clean air filter, all help too.