A couple of my thoughts...
This unit is approximately 3 years old now. Have you shopped around for a new unit? Take a look at this:
https://lakeshore-rv.com/hideout-rv/...28bhs/l-32680/
I bet the dealer is around $19K before taxes, plates, and $200 paper work fee. How do I know? I purchased from them over 2 years ago. All their units include a PDI, battery and propane at no extra cost. Toppers are about $500-550 each installed.
So to sum it up, you'd be getting a brand new unit for just under $20,900 (assuming 6% PA sales tax) plus the cost of your plates.
Personally, I know what I would do. Road trip anyone??
BTW, the dealer above is top notch in terms of sales, customer service, responsiveness. Sales Mike, Warranty Mike, and PDI tech Michael were my points of contact and are recommended.
The other thought I had was regarding your bunk situation with 3 young kids. The 28BHS isn't a bunk house, but rather 2 full size bunkbeds, adjacent to the living space. Have you thought of buying an actual bunk house floor plan? This would give your children some highly desired floor space on rainy days, and even some surely deserved privacy as they get older. Remember children grow like weeds. I know I have three of them at 7, 4, and 3 years of age and having the closed door "bunk house" is a saving grace on long trips. Plus it gives mom and dad some privacy too. For a just a little more than your current budget, you'll be able to find a very nice Keystone bunkhouse from a variety of their brands (Passport, Bullet, Hideout). A couple of examples...
https://lakeshore-rv.com/hideout-rv/...29bks/l-14674/
https://lakeshore-rv.com/passport-gr...920bh/l-21873/
https://www.ebay.com/itm/2018-Keysto...0/132569734862