Lastly, ignore the "dry" weight of the rig, only pay attention to the max GVW of the rig.Well, not exactly. Your concern should be CCC, or Cargo Carrying Capacity (GVW minus dry weight). This equates to the amount of "stuff" you can pack, weight of liquids in tanks, and passenger weight (for non-tow behinds). If your GVW (Gross Vehicle Weight) is 10000 but your dry weight is 9000 lbs that leaves you with 1000 lbs CCC. Sounds like a lot, but it isn't. If your GWVR is 10K but dry weight is only 7500 lbs, you have a lot more CCC.
If you get your tow vehicle first, then you may possibly limit what you can buy for a trailer. If you get the trailer first, then you may be forced to buy more vehicle than you want Chicken and the egg proverb comes into play. Always buy more truck than you think you'll need as chances are since you are a newbie you'll be changing your TT within a year or so.
New = bigger up front investment but any issues covered under warranty.
Used = less up front costs but any potential repairs are on your nickel.
We always bought new because we could but we started small with a pop-up then progressed up to a Class C. No longer RV due to multiple factors but have many years experience doing so. My last piece of advice is to not go hog-wild on the off change you really don't like the lifestyle. You can always trade up if necessary and if you are like the most RVers you will change your mind multiple times as to what you want.
I may not have gone where I intended to go, but I think I have ended up where I needed to be
Douglas Adams
[purple]RV-less for now but our spirits are still on the open road. [/purple]