There is often no "one size fits all" generator, it really depends on your "needs".
Small gens are great for portability, use less fuel but leave you limited on how much it can power.
Bigger gens will power anything the small gens will plus even bigger loads, but they use more fuel and often are not very portable not to mention noisier.
What you need to determine is what exactly you are wanting to power. Add up the wattage of your intended loads for your home like fridge, lights, water well, furnace and such.
Keeping in mind that small portables (4Kw and under)often are 120V only and larger 4Kw and above are 120/240 (many of these you only get HALF the rated power on the 120V outlets).
There are some like Champion brand 4KW gens which have a switch that allows you to combine ALL power into one 30A 120V RV outlet (handy for your RV).
For your RV, while some folks often getaway running their A/C from a 2KW gen it is on the edge of not being able to do that consistently so you need to consider two 2KW inverter types which are the only ones that can be paired or at least a single 3KW gen.
Personally I have a 4KW gen for my TT and my home, plus I have a 2KW but it isn't very useful and I am thinking of getting rid of it. I am now looking at buying a 8500W Harbor Freight gen which is going for $599 for my home and keep my 4KW one for the TT.
My 4KW gen doesn't have 240V and I need 240V to run my water well during power outages. The Harbor Freight gen would power my water well plus a lot of other items and it has electric start option which would be much easier to deal with in the winter.
If you had to make a choice size one for your TT then if you want a bigger one to run more at home buy it it later on..