I'm not sure you'd want to carry a microcomputer on your bike

Smartphone is not a good idea for use as your primary GPS for many reasons that were mentioned in several threads on this forum: short battery life, delicate, not waterproof, inadequate software, difficult to operate with gloved hands, require proximity to cell towers for best accuracy (assisted GPS). Get a real, rugged GPS receiver, a cellphone is most comfortable stashed away in a cozy case, preferably waterproof

Solar chargers were discussed here.

As far as carrying a computer it's up to you. Some people carry laptops, some don't and use libraries for internet access, some are strongly against the idea as they like to leave the tech behind them. I'd take a netbook along. They're lighter than a regular laptop.

It's really up to you: how much technology and connectivity you need/want and how much you're willing to carry.

Adam