Yes, the Sprinter 3.0L diesel is turbocharged. Your 2015 Solara should be able to handle the Wrangler but verify its weight and check the Jeep owner's manual to confirm it can be towed 4-wheels down. It most likely can but you should still check.
I have our 2014 Honda CR-V AWD (approx. 3400#) set up to be towed behind our 2016 Thor Synergy (M-B Sprinter too) and the Thor handles the load just fine. I have towed it from North Carolina to Beckley, WV and the interstate grades pose no problems but I have yet to tow on 2-lane roads with challenging terrain.
Fuel economy while towing only seems to drop about 1 mpg so it's safe to say that the biggest impediment to fuel economy is the Solara's front profile. Non-towing we get between 14.5 mpg (strong headwinds) up to 17 mpg but I tend to take it easy on the skinny pedal. That being said you should be quite OK with a 26 gallon fuel tank. The Sprinter Class B+ and Class C motorhomes are quite easy to refuel since you can pull up to an automotive diesel pump which is more convenient than the big-rig fuel islands. You might also consider getting a Scangauge or some other type of OBD II reader to monitor engine systems.
Ed and Robin
Travelling buddies: Nina, Kit and Mickey
2016 Thor Synergy TT24, Ming Blue
Mercedes-Benz Sprinter 3.0L, V6