you need to make sure that the generator can handle the wattage you're throwing it.
Some generators rate themselves at their MAX LOAD which is not so safe to run at consistently, there's one which rates itself 800w but if you read the manual it's more like 650w...just be careful.
If you want to find generators just go to The Green Book and type in Generators.
They're very heavy, just to warn you first.
If you are looking for portable outdoor lights Profoto rents out their packs, alternatively you can contact me as nearly all my lights are outdoor battery packs.