the tripod won't come close to supporting the trailer. they are just snugged and should stop some of the shake. my experience is that they do very little. i used one for years then put the stabilizers (braces) on the landing gear and rear feet. they really work.
i don't know what ur time table is, we went in 2002 and had reservations along the way. we didn't stay in Yellowstone but in Cody. the only campground that we stayed in was in Custer SD that i don't believe we could have gotten in without reservations.
in 2004, we had an itinerary but not a timetable. saw the places we drove by on the first trip...corn palace...and we got our free glass of ice water.
we would call ahead to our next destination and reserve a spot while on the road. we had enough flexibility that we could change destinations if we were unable to book.
while at Yellowstone, i highly recommend US 212 thru bear tooth pass (without a trailer). that goes to the NE entrance to Yellowstone. we found that scenic drive worth the trip.
the last trip, we drove across US 2 to glacier. we go 300 miles on a fill up and made it to a station just in time twice.
enjoy ur trailer and ur trip.