I doubt you'll notice much difference. The Ram is the only 2500 that rides and handles better than its 3500 counterpart, imo. On the GM I'm not sure if the 2500 just has slightly softer rear springs or if it lacks an overload spring.
There's very little practical difference between any of the SRW 350/3500s versus the 250/2500 (minor caveat being the Ram where the 3500 allows you the option of going to the Aisin and HO Cummins). Really for any TT or a 33' fifth wheel any of new SRW heavy duty trucks would work great. Pick your preferred flavor and enjoy. The only thing you might want to check out is whether there are any additional registration fees or other headaches associated with the higher GVWR on the 350/3500 in the city/county/state where you live, but I doubt that's an issue in Oregon.
DRW would definitely move you up a notch in capability but for the type of trailers you're contemplating it would be totally unnecessary.