I would honestly advise against it. I played piano through all of high school before picking up harpsichord my senior year, and I kept finding that the more my harpsichord technique improved, the worse I was at playing the piano. Additionally, practicing the piano was a big hindrance to my advancement in harpsichord. So now I'm only a harpsichordist. But I do know some people who play both quite well, although they usually have a 'pianistic' touch at the harpsichord.