One of the things the dealer is doing on our new 378TS is weigh it corner by corner. With gas, water and propane full. It is important to know your starting point to help you load it properly and add accessories, such as a washer/dryer.
I am supposed to take delivery Tues, and when I get the info you requested, I will let you know. We did a quick inspection and test drive this morning. It appears the front slides are 24-30 inches, but I didn't measure them yet, but I will and let you know.
Happy Trails, fbconsults
(Forrest and Donna)