What is your base workout vs. race distance?

For instance, if you are focusing on the 5k is your base workout 5,000 M? How much of the distance comes from the main set? I've pretty much settled in on the 2000-2500 distance three times a week during the pool season and then switch to longer sets for the summer. Yesterday I got up to a 2800 yard set consisting of 2x200 on 3:20 and 1x 400 on 6:40, repeat, trying to maintain my goal 1:30/100 pace for a mile. I'm curious how far I away I am from the training I need for a 2 mile or even 5k. Obviously, I'm not trying to win or anything. I'm thinking I could possibly even do it now if I relaxed and went easy, but I don't know. I've never been able to get myself to just do a straight swim, unless I am in a lake (which I haven't been able to do yet this year).