Yes, solar can be added later... but I wish I had moved on it earlier. Listening to a generator for 4 hours at a time can get annoying. And you can even run solar and another charger in "parallel", and they will add their amps. The secret is setting their voltage outputs the same.
A properly sized system will essentially allow you to boondock forever. But as others can tell you, power is not what limits one's stay... it's water and food and fuel that are in limited capacity when boondocking. Gen charging is, of course, limited by how much fuel you can carry, while solar is limited only by the availability of sunlight. Therefore, one should either size their battery bank accordingly, or have a generator as a back-up charging source, but not as the primary source.
If you think you'll make good use of a 30a system, go for it. But if it will only be used on the rarest of occasions, it may not be worth the trouble and/or cost? I have become quite the power miser, but going solar in the near future has already got me thinking I may need to become a little more "wasteful". :)
