If I had to have only one vehicle it would be an Excursion... too bad they stopped making in 05. Easy enough to increase the payload as the chassis is nothing but a F250 which can be increased to a F350... extra rear spring or airbags.
I helped my daughter buy a new 2000 EX with the 7.3 which they still have without any major problems, not even the tranny. What else will haul seven adults and get 20 MPG at 70 MPH... Yes, I've done that several times with the AC on.
I've even thought about getting rid of my 02 F350 7.3/6 spd for a 05-07 6.0 because of the video in the clicky below and being close to his shop. Probably the shortest education on all the Ford diesels you could ever ask for.
Recent post and
Video. Depending on amount of miles expected, a 05 EX with the V10 might be a better option.