If you add up all the watts you would use at one time, you times it by a factor of three and that will give you the Wattage/KVa genarator you need.
A generator needs a motor to turn it, to generate electricity.
Any generator with a Honda motor are very good, but as in all things maybe exxy.
There are a million chinese imitations of the Honda motor generators on Ebay.
Most generator websites will assist in working out what size you need.