As far as the prices of trailers are concerned, my crystal ball is fuzzy, but here are the factors which I would consider:
1.) The 2021 projected rate of inflation. The 1980-standard is on a trend of 18% and the CPI-U is 8¾%. This is calculated from the January to July actual increase times two.
2.) The customer demand. I have read folks on this forum speculate in both directions on this, but I feel the demand is fairly constant and will be so through May of next year.
3.) November seems to be a good discount month but with the backlog still high, who knows?
I personally prefer a black water tank. We have free dump stations at the rest areas here in Washington, and used with an adequate amount of flush water, it seems to be less mess.
I would add that as you tour, try to do the Oregon Coastline going southbound. US 101 is a two-lane highway, and most of the scenic turn-outs are on the ocean-side.
Here is the brochure for the 2020 1800 Bunk House:
I agree with the goal of getting a Bunk House trailer. I believe it is very comfortable for the kids to have their own space. Let us know how it goes, OK?
Welcome to the forum.