Castro Valley and Fremont are more desirable from an investment perspective since the schools are very good and you will be able to rent it easily. Plus when you want to sell the property, it will have more buyers and the appreciation will also be higher than the other cities. But then, keep in mind, you will be paying a higher price to begin with because of the demand in these 2 cities.
Help-U-Sell Achievers Realty
Fremont homes will rent for a higher amount, however they will also cost more money.
There are many people looking for housing from Fremont to San Leandro so you should have no problem renting. We would need numbers to help with your rate of return and monthly cash flow.
There are homes in the Hayward / San Leandro area for under $300K that are nice homes in nice areas, but the best you can do in Fremont might be under $400K.(if lucky)
Sit down with an agent to go over the numbers.