Mondooker, you seem to have your head very much screwed on, and nothing is worse than the Fear of Fear itself. Don't meet trouble half way is what my grandmother always used to caution me = I'm a total worry wart, and finally recognize that with me "too much analysis leads to paralysis".
I only write our story here in case it helps others in their thoughts following your reference now to maybe considering a Gas RV versus a DP - the latter we have no personal experience with
Bottom line is after deciding on your budget - decide on your comfort level - what floorplan will suit your style of camping/rving/traveling. Just these things alone will lead you to type of RV, length etc.
We started with a fifth wheel back in 1999 as we could utilize the engine(truck) for hubby's work at the time and we were only RVing a few weeks each year, and I wanted as low a depreciation when sitting more than moving travelling in it. In 2002 hubby wanted a coach - still working full-time, and with the exchange rate against us, plus the fact he then was a "gotta have new guy" I decided we could buy an awful lot of gas for the extra $100K a DP would cost us at that time.
As time has progressed and we are moving now into retirement and intended FT within the next year, hubby's persistent push in the past decade wanting a DP seriously raised it's head again. As much as we both love the idea of the new sparkly Entegra, Tiffin, Newmar 40/42ft coaches we keep now coming back to the concerns of costs of maintenance and how much downtime we see others have with all these new system/technology advances on them = "more things to go wrong and repair/maintain". As well at 37ft, we know we get into almost everywhere we want to being avid dry/dispersed campers for the most part.
Whilst we are compared to some folks I'm sure, blessed with having been workaholics most of our lives and socking $$'s away for retirement - I worry terribly about stretching the monies beyond the next 30 years (just in case!), so trying to keep our outgoings minimal, at least initially until we get a good handle on being on the road and returns on investments established. Of course this has recently been even more compounded with the reality check due to the huge drop in the stock market, our local RE market collapsing being the energy province and the exchange rate having moved exponentially from the PAR so many of us got used to.
The thing with our gas engine that we've had for about 14 years since new, is we know most of her intricacies, maintaining her and so on. Yep for sure a newer DP is quieter during travel days, and we'd get up the hills a little faster, but we currently as we are do get up the hills, just arrive a few minutes later than our DP cousins. Well that's what I keep telling hubby to try and keep him at bay.
FWIW, aside from a few hundred bucks for oil changes and maintenance, and a ridiculous amount of changing out tires over the years, until having an alignment and new tires last year (we were royally ripped off on the alignment and leafs!), just in the past 3 years we had a new engine at about $7K cost inc labour, replaced RV fridge for a residential style one at IIRC about $600 inc trimming out, replaced our old Tube TV for couple hundred bucks inc trims - and our other biggie was the 1000w 800ah solar install last year (we love to be off grid more than anything). All in all when I added everything we've ever spent on her (I keep very good records and journals of all costs/trips etc) She has averaged us about $1500 per year spread out over the lifetime we've owned her. The majority of that has been in the past three years. We do our own oil changes/filters, generator servicing etc.
Going forwards we are allowing $200 per month in our budget to top up the RV maintenance fund, with a base lump sum put in it of $10,000 to start with.
As I said Mondooker, hubby in his heart of hearts would love a DP NOW, but I just can't justify the higher upkeep costs just yet, until we have a firm feel for how living FT on the road in retirement (two huge life changes for us at once but current economic demise), is going to pan out financially for us.
FTW, aka "The mean other half" (LOL).