Your criteria may be able to be addressed with a 1000W Honda Generator. It won't add complexity or failure points to your systems and won't take up perminant space or add perminant weight.
Seems to address your occasional need for base camping. If it doesn't satisfy you, the resale value of these little gennies remain sky high. List it, sell it and test the next solution.
Just too bad they only put out 100W on DC which is really what you need. Better to build a home-built, gas motor driving a cheap GM alternator.