I wouldn't rush out to get a second battery, generator, etc., now. Give a 3-day camping trip a try and see how you fare first.
I found that I don't need any of them - I have more than enough power for how I camp with the one house battery. If I had bought a generator, it'd be sitting around taking up space for nothing; a second battery or even solar power would be unnecessary money spent. If, at some time in the future, I find my needs change, then I will consider the choices, but for now I'll save my money.