The short answer is yes, because as a theoretical biologist you will often find that the measurements or observations you need simply haven't been done. Collaborations sometimes work, and often last for years. But you can only understand the reliability and richness of data by getting some yourself. Thus training as an experimentalist is very important for theoretical biologists. The best training is in someone's lab, going beyond what you get out of laboratory courses.
Theoretical biologists are somewhat like square pegs in round holes.
Being a part-time experimentalist reduces this necessary tension, which will last so long as vast areas of biology remain near virgin territories for theoretical understanding. You need a lot of self-motivation. You should pursue a 'career' in Theoretical Biology if, and only if, you love it. That is, if and only if a day would be unbearable without it. What to Read Books You will find hundreds of theoretical biology books in any university library.