Go to your loca Pull A Part or LKQ yard and look at older conversion vans. They always swivel seats in the front and many times in the rear if they have second row bucket seats.
Look at and or remove one of these swivel pedestals/assemblies and see if you can fabricate brackets to use a swivel in your Excursion. One thing for sure is that the swivel brackets/assembly will be CHEAP to buy so your not out a lot of money to try.
Biggest problem you will have is the answer to this question:
Is there enough room to swivel the Excursion seat within the confines of the truck?
Attached below is an example of a swivel and removable seat base that I removed from a conversion van. Paid $15.00 for the assembly that bolts to the floor and has the ability to remove the complete seat while leaving the attachment plate still bolted to the vehicle floor. Use the complete assembly or just the swivel part to fabricate something to fit a truck or Excursion.
As far as the 4WD van or I assume you mean a 4WD Excursion question since you did not specify. I have a 4WD van, 2WD and 4WD PU trucks, and a 4WD Suburban and they all have there good and bad points. No one vehicle is good at everything.
For traveling i comfort over a long stretch of road with a family it's hard to beat a Conversion Van with all the appointments and comfort they provide. My preference would be a GM AWD conversion van assuming your off-road experience will not be much more than Forrest Service road off-road capability. A 2WD conversion van is not good for much else other than super comfortable traveling and maybe campground camping. A GM AWD equipped van can be made into a somewhat capable vehicle with some work and understanding their limitations.
A true 4WD equipped van is nice IF you have a need for this type of vehicle as they are expensive to buy, have unique characteristics due to the 4WD conversion and then you have this issue of how the inside in configured. As far as repair Van parts are available anywhere along with mechanics that have knowledge to make repairs.
The Excursion/Suburban choices are a better choice than a AWD conversion van IF more than Forest Service road off-road adventure is what you want. However given the Excursion/Suburban size (same or bigger than a van) are not going much deeper if at all into the Boonies any further than a properly equipped 4WD van. Seating is comfortable in the EX and Burb, seats remove giving you a covered bed PU if you need haul something. Just remember the 4WD van will do the same thing and maybe do it better. Then there is the diesel/gas debate as everyone seems to go GA GA over 20 year old 7.3 Powerstroke Excursions along with the pricing to match.
"I" think the question you need to answer for yourself is are you willing to have multiple vehicles to do different tasks or just one vehicle that does everything you need just OK? If not more than one vehicle what is most important to you and what compromises are you willing to make as NO ONE VEHICLE does everything perfect therefore YOU must decide you must have and what you are willing to give up!
Below is my $15.00 complete swivel seat base from Pull A Part!
