A van would be a nice choice for a Silver Streak.
For GM, do some homework. I know that the VORTEC-series engines feature better power and life than the previous generation. I would hold out for that. A V8-350 [5.7L] is a bit small for a 26' or larger trailer. It'll do it, but it'll work for a living (my preference, but many are afraid of an engine running 3000-rpm all day when called for) and an excellent choice for service and solo. I would specify a 3/4T van.
Depending on the year/model the TT GVWR will be no higher than 8k, and, loaded for full-time travel (full water, propane, etc), you're looking at likely 6500-lbs or more. Use 7k as your guideline for trailer weight.
We full-timed in our non-modified '83 34' (see sig link) and were at 92% of GVWR [7,400-lbs +/-] the times I weighed the trailer. I recommend, heartily, a PRO PRIDE hitch for any TT or TV.
There is/are more than one SS owner in the Seattle area. Please go to the Toms' Web Page
site and sign up for the Silver Streak
Mailing List. While it is unlikely that SS's ever leak, you'll want to avoid this as with any other brand if possible. Post pictures of what you are considering. It may be possible to get some feedback from other owners about "what" they see in any photos.
If we ever sell this house another SS is at the top of the list for us. There aren't enough post-1972 Streamline
trailers (all brands: separate black water tank, a must, IMO), nor were many made in the rear bedroom configuration we wish to have. I'd love to own one. Same for AVION, there are many of the config we prefer thru the 1990 model year.
I would recommend to you the 1973-1977 AVION
(prior to their acquisition by Fleetwood; but after black tanks were standard). While the later trailers are fine, I believe that this model range is an outstanding value in current price and overall construction. Superior to SS for it's foamed insulation, IMO, and it's walking beam suspension (called "Smooth Glide").
For a single person a 28' of these years with the double bed is the way to go. Much superior to anything built by A/S in this period in every regard, but especially initial price and price of repairs [scale] necessary, if any.
Here's a '73 28' for sale in Springer, OK (OKC). This trailer would weigh above 5k for travel, maybe 6k if loaded heavy:
Fabrics, floor coverings, etc, are all easy to change. With these orphan brand trailers remember that all appliances (A/C, refrigerator, etc) are all the same. CAYO [MI] still is in business furnishing parts as necessary (limited).
With any of these older trailers have the axles aligned, change the exterior marker/signal/brake lamps to LED, and do the "on road" items quickly with any budget constraints. Brakes and tires: make 'em new on the TT and TV. The ugly carpet will wait (my wife and I lived on the subfloor for months. Used area rugs).
Tin Can Tourist: 31' Avion