I have not heard any bad reviews of Nash travel trailers and have heard lots of good reviews of Northwood quality. And you can option a Nash to get the same 4-season livability as the other Northwood trailers.
Our trailer has exactly the same floorplan and the GVWR is within 200 lbs. of the Nash 26N, but is 3' shorter due to being a 5th wheel. We love our floorplan for the same reasons you mentioned--length appropriate for NPS and USFS campgrounds, all weather and boondocking capability (AC/propane fridge, thermopane windows, two 12v Fantastic fans, 12v tank heaters, duct-heated basement, LED lights, 2-30-lb. propane cylinders, lots of basement storage, etc.), and a nice, big rear picture window. It also has the 25N's split bath, which is very nice when we are getting ready in the morning and would be an absolute necessity if we had two teenagers with us. We have also added 2-6v AGM batteries and a 235w solar panel to make it even more "boondockable" (did I just invent a new word?).
The downside with our floorplan for you would be converting the sofa and dinette to beds for the kids every day. And our sofa is likely too short for a teenage boy. So, the Nash 25C bunkhouse floorplan might be easier for you now, but you would have to give up the rear picture window and the dinette may not really be comfortable as the only seating area for a family of 4. However, at 28' 8", it is within the range you mentioned for convenient national park/forest camping.
The 25C floorplan is very similar to our previous travel trailer (although we had no bunk beds)--a Rockwood Mini Lite 2109S. But that trailer got a little too claustrophobic, even with just my wife and me in it, during our 3-month trip to Alaska. So, we found, just as you did with your previous RV, that upgrading for differing family conditions and desires tends to just be part of the RV lifestyle. No one RV can fit every situation.
Have fun shopping for that perfect RV and even more fun camping in it! And especially enjoy camping with your kids because they don't live at home forever (says a father with a grown son living 8,000 miles away).
"Retirement is the best job I ever had!"
2015 RAM 2500 4x4 crewcab 6.7L CTD; 2016 Rockwood Signature UltraLite 5th wheel