The Excursions are really cool and there have been a few recent threads on them here on Expo. I do not own one but I have been around them enough that I'll try to give my best opinion and advise. If you're thinking Diesel (or V10 for that matter) the Excursion should easily be able to pull that trailer, all your gear--and then some!
I would shy away from the 6.0 diesel and the V8 gas engines (that topic has been beaten to death so I won't go into details) and I would highly recommend finding the 7.3 for its well known reliability. Their Drive train is very stout and if the transmission has been properly maintained there should be few problems there. There are a lot of engine/fuel system related parts that can give you a real headache if they were neglected so really spend the time to find one that has been cared for and not abused.
The only thing I can really add is they come with the 3.73 axle ratio so keep the tire size down or you may put too much strain on the transmission while pulling. A good set of gauges on the diesel (trans temp, pyrometer and boost) will really help you out in the long run.
91- F350 crew - Turbocharged IDI