Since running the house is probably going to require the most power you have to decide what thinks in the house are the must have items for you. Then consider what it's going to require to take that size generator with you on the road (easy lifting, noise, etc.).
Using some power management I can run everything in my trailer with my Yamaha 2400ishc. The 3500 watt generator I have at home to run heating or A/C, frig, lights, microwave, television, computers, etc. is just to heavy to bring camping and a bit more noisy so I opted for a second generator (the Yamaha) to take with us when we travel.