I know this comes up often enough, but have you done the Baja before? It would be a fairly cheap flight over to San Diego and then pop down. You can get by with pretty minimal Spanish just because there's so little there, and your daily costs would definitely be pretty low as well. South of San Vicente the entire peninsula is pretty much yours for camping, so stealth camping doesn't require a whole lot of 'stealth', and there are still a few options of paid accommodation around. Two weeks is about right to get you down to La Paz, especially a bit easier if you bussed the first section to around Rosarito, and then cycled from there. Beautiful, cheap, and the weather should still be pretty decent in January - dry, warm during the day and a bit cool and night.