I do plan on trying to save some tomato seeds this year. One is a California Gold tomato. The question I have is, do I have to worry about cross pollination of the seeds I collect as they are next to some Beefsteak plants?
Tomatoes are inbreeding plants and the anatomy of the flower dictates the risk for cross-pollination. If the style is retracted them there is little risk that the flower will be receptive to pollen from other sources, but nothing is 100% in nature!
As a general rule, if in doubt, I always recommend to bag the flowers. It's pretty easy to do and then there is no risk at all that the next generation is an accidental hybrid.