Hepcat, I average 23-25 mpg pulling my Aliner. It is a medium sized model but has all the bells and whistles. I met a fellow pulling a snoopy dog house motif Aliner with a VW Jetta diesel who says he gets 30 mpg towing.
If you go to the Aliner Yahoo forum they have a database that contains info from Aliner owners with tow vehicles, tow weights and mpgs.
https://groups.yahoo.com/neo/groups/alinerchaleta-frames/database/26/edit
I think you must be a member to access the file, but just in case you do, here's some info contained therein:
Subaru Outback 2.5L 2007 Sportliner 21 hwy mpg
2010 Subaru Forester 2.5 2009 Aliner Classic ST-2 2000 lbs 22-23mpg
2003 VW Golf, 1.9L I4 TDI (diesel), 5spd manual 2010 Aliner Classic ~1500-2000lbs 26-30mpg
1987 Toyota Pickup 2.4L 4cylinderR22 2004 Chalet LTW 1395lbs 23 to 24 MPG Up to 60MPH
Mazda 3 2.3 1996 Aliner Standard 22mpg
2010 Toyota Yaris 2dr , 105hp/103ft.lbs. 1.5 Twincam 2005 Aliner Sportliner 920 lbs 33 MPG highway, 29 city
1995 Ford Taurus 3.0 v-6 2009 Scout 1400 20 - 22 mpg
2010 Subaru Outback 2.5i with 6MT 2011 Aliner Ranger 24 highway mpg
2009 Pontiac Vibe 1.8L 2009 Aliner Sport 1720# 22 mpg avg.
2007 Honda CRV 2.4L 4 Cyl. 2012 Aliner Sport 1500 lb 21 mpg
Toyota Rav 4, V6 with Tow Package 2012 Aliner Classic, Titanium Edition 19-21@ 65 mph, depending on grade and wind conditions
Honda Element 2.4L 160 HP 2013 Aliner Alite 26 mpg
Of course there are tow vehicles that get less mpg, particularly in mountains, but there are many who exceed my 20mpg projection, as does my combo.
BTW, I have over 369,000 miles on my Chevy Cobalt (original engine, but auto tranny replaced at 300,000 miles), over 65,000 of which have been towing my Aliner over varied terrain including many mountain ranges. It averaged 24.1 mpg towing my Aliner at 65 mph on my last 2,500 mile trip (mostly flat land till I got to the Chisos mountains).
I absolutely agree that depreciation is a huge variable. That is why I left it out. If one buys a new $100k+ MH, the depreciation will far exceed operational expenses. However with a 10+ yr old, low mileage gas MH in the $20-$25k range, depreciation becomes a lesser issue. Certainly a suitable, used economy car and a good used Aliner can be had in the same price range or less, making the depreciation comparison between the two roughly equal, which is why I didn't include it in my crude analysis.
Chip