Looking at buying a TT. What size Generator is needed?

You will have plenty of advice about inverter or non inverter, and brand, and those "awful contractor" generators. Start with the basic question - how much load capacity? Generators are rated by watts. Volts x amps = watts. Volts figure at 110. Does your camper have 30 or 50 amp service? Do the math to figure your wattage requirement. You can build in a larger requirement if you are thinking upgrade in the future, or maybe for use at the house if power is out.