Can you freeze the tomatoes and then use them later to make a large batch of spaghetti sauce, salsa, etc. and then either can or re-freeze?
Sure! If it is just a matter of days or a few weeks, that works great. I just do the prep steps to the point of producing the prepared pulp (through step 7 on this page http://www.pickyourown.org/canning_tomatosauce.htm ) then freeze in a ziploc bag until I have enough to them heat them altogether and finish the process.