I just returned from a 2500 mile trip (round trip Seattle-Barstow) with the rig setup in my profile. Most of the trip was about 19K lbs GCW and the last 100 mile leg close to 20k lbs GCW. I had no issues crossing windy passes and climbing over 4000'+ twice in each direction.
I figure I had to upgrade my SRW truck with $2500 of additions to be able to do this safely over owning a DRW. I would not be able to upgrade to a DRW for that price without going to older or more worn truck. If I needed to buy a truck for this purpose, I would have no hesitation to buy a DRW instead of upgrading a SRW.
May will be a short 500 mile trip over a 3000' pass and June will be another long 5000 mile round trip to St. Louis over the Continental Divide.
It is possible to do all this with a SRW, but easier to start with a DRW...