I take back my gasser recommendation because of the following: "probably use July-October" sounds like retired with the kids out of the nest so the 3-4 months will probably increase. I always recommend to not buy a DP unless you are going to use it 100+ days/year. I also recommend buying more MH than you think you need ONE TIME... I started with a used 36' DP because of post on here that 36' was the biggest for SP, USFS, NP. Did not take long to realize that's not true so traded for a used 40' single slide DP. Once we could use a RV more than 100 days... 42' and four slides and we boondock often. Hopefully you live in south TX so no need to snowbird in the winter.
My MH is in your age group and I plan on keeping my 04 for another 10-15 years when I'll age out, not it. I've replaced my analog TVs with LED TVs. I recently bought a new old style Dometic AC as a spare for the three that I have because of the difference in the newer control systems. I recently gave up on my NoCold 1200 refer and replaced it with a home refer on it's own battery bank and charger/inverter.
Around 2002 DPs started gaining weight (more slide, tile floors, AquaHot, longer lengths....) so the CCC decreased to not enough. The good solution was to add tag axles which increased the CCC to 9000+ and improved the handling. The amount of CCC a rig has should be posted behind a cabinet door somewhere... very important. We really do not need two slides in the BR but in order to get two in the LR... you end up with one or two in the BR. When overnighting at WalMart we usually put one out so the DW does not have to crawl over me in the night.
I do not share the concern about the frames not being up to the task... that's more a gasser problem where the back has been extended. I would not rule out a brand that's no longer in business as the drive train of a DP is more truck than RV... Cummins, Allison, Bendix, Eaton.....
04 was the first major change in engine pollution requirements so do a google search on Cat Acert engines. 07 was the next even bigger change and Cummins was able to use credits from their 5.9 to use against the ISC, ISL, ISX engines that did not meet the new standards. Cat did not have any small engine credits to use and finally gave up in 2010 on meeting that years even greater requirements.
It's a buyer's market without a trade so take your time and enjoy the search. If you are near PPL Mothorhomes they have plenty of rigs to look through and have a good reputation. Good Luck
