You're going to have a very difficult time trying to find streets that you can park on for 5 days a week every week.  How long do you plan on doing this?  A year?  Five years?  Forever?  What happens when your RV breaks down and has to go into the shop for a week? 
Do you really think no one will notice the motorhome parked on the street all week?  What about your other vehicle(s)?  Or are you just going to use the motorhome to get everywhere in the Bay Area?
I understand your dilemma regarding housing costs in the Bay Area, but this is just not a viable solution.  You are better off putting that money towards a cheap commuter car or amtrak passes and living further away.