Finding a decent 'bullet proofed' Excursion would be the way to go. It's a 3/4 ton-F250 chassis and capable of doing what you need. The 6.0L is a great engine IF the maintenance was done per Ford's spec and the engine had a clean 'Oasis' (Ford's computerized service records) report.
2010 Cedar Creek 5th Wheel 34SATS "The Beast"
2006 Ford F350 Lariat 6.0L Diesel
2003 Harley Heritage Softail "Hogzilla"
1988 Harley Softail Custom "The Fireman"
1986 Marriage to "Wifey" (patience of a saint)