Sorry about not seeing this one.
In the CCENT and CCNA series we just connected 3 routers together in ring for the Routing portion of the shows.
With the switches, we did a full mesh between 3 switches for vlans, vtp and spanning tree too.
Reconfigurations for setting up Router On A Stick, by connecting a switch directly to one of the routers. If you wanted to do this also with a Layer 3 switch, it is also possible with your 3560 and 3750 switches too!
We didn't have any 3750 for the stackwize stuff.
*if the post above has answered the question, please mark the topic as solved.
**All "answers" and responses are offered "as is" and my opinion. There is no implied support or guarantee by the ITProTV team.