About half way thru my first spring training on this site and looking at my roster for the season closer (didn't have time before the season started as once I joined everything started) and would like to run a 5 man rotation with 2 of the spots in that rotation being tandem guys. Is there a way to set them up to have a SP1, SP3, SP5 and then SP2 and SP4 be tandems? If that can't work is there a way to do SP1, SP2, SP3 be regular starters and SP4 and SP5 tandems?

You can approximate the latter option, with SP1, SP2, SP3 and T4A & T4B. For some reason tandems won't work with slot 5.
If you log in frequently, you can shuffle your pitchers around enough to create your own 5th slot with tandems, but it is a lot of shuffling everyday to put the right, rested guys in the right slots.

Would using SP1, SP3, SP5, T2 and T4 work?

No I think it has work in order, where tandems can only occupy the last slots, or all of the slots. It's one of the more byzantine rules in the game and I've never understood the reason behind it.

Yeah, you can only run Tandoms as the last spot(s) in the pitching order.

Correct. Tandems in the last two spots (3 and 4, there is no tandem 5). You can still work with a five-starter rotation if you rotate your three non-tandem starters in the 1 and 2 spots. Like once No. 1 has started, you put No. 2 in the No. 1 slot and put the third guy in the No. 2 spot. The the tandems at 3 and 4. You can start the process over again. You just have to stay on top of it.