I have a 1kva Honda for many years and take it on long trips for all the reasons listed above .
Just spent 5 days at sandy creek with the 300w roof mounted.
I had to have camper in sun all day to get the amps in with the roof mounts .. Bloke across from us nice shady spot by creek under the trees 2 hrs a day on Jenny and he was done .. While we baked in the sun.
Solar is awesome but has limitations esp in a roof mount scenario such as what we have now .. I will most likley take 200+ watts portable on my trip as the roof mount is now just a bonus not to be relied upon as baking in the sun is no fun and reminded me why I prefer portable panels .
Get a 1kva just in case is my thoughts . I don't run them to annoy others and that's another debate but as far as usefulness you can't beat em on a long trip . If you gave an alternator issue or similar a geny and charger can get you through it out of trouble .
Jet