Regarding MP, they've stated that it might be something they'll look at after the full release of the game, but there are no plans for it right now. They are a team of about 27 according to their Trello board.
As for having to start over again, there's a way to preserve your game when there's been a big update. There's a video by IGP explaining how to do this:
https://www.youtube.com/watch?v=r97PcLuThHg
And also, if your game starts to get really laggy, you can use this tool to resolve the issue, but be aware that it resets all the node spawns and resources in the game, along with everything that spawns at wrecks etc so use at your own discretion. I personally don't feel it's a problem because stuff is freely available anyway, you just have to look for it, but some think it's cheating because it effectively makes the game easier. I am just happy to get a lag-free game after playing for a while.
The tool is here:
http://forums.unknownworlds.com/discussion/146898/made-a-tool-to-clean-cache-crash
Last night I got my Cyclops built, and I've put some more lockers inside to make it a mobile base. I managed to find fragments for the power cell charger (after mistakenly thinking that the Cyclops automatically charged them, damn it!), and also fragments for a Nuclear Reactor and a modification station. So now I need to find myself a good spot for a proper base! I'll be on the lookout tonight. I was thinking about heading over to the Grand Reef to maybe get something there, but I've never been there so I have no idea how hostile it is over there. I don't know if I want to build my base right inside hostile waters! Does anyone know if the Grand Reef's position enables you to get to all the other places fairly fast? As in is it in the middle of the game world?