Mac Pro :: How To Handle Switching Between Systems

I have my Mac Pro 2.8 8 core as my main machine. And my MBP 17 as my 'mobile' workstation when I'm on the road or out of the studio. I back up my MP system and files using CCC to an external drive. Usually I manually copy just the working folder of files that I need to my MBP and work away. When I get back to the studio I manually copy the same folder back to my MP. The question is.. is it ok to boot off my MP System + files backup off the external drive while connected to my MBP? And work off it. Both have system 10.5.7 installed. Will there be any problems with booting off essentially a MP configured system while working off the MBP's hardware. i.e., will there be any conflicting system files that may get confused and screwed up?

If it was safe, then I could essentially cloned back from the MP external sys+files back up - Back - on the MP. Just wanted to get some opinions and advice from others who probably have similar dual workstation & mobile machine set-ups. Just wondered how you handle the switching between systems? I just don't want to risk cloning back from the external to the MP and risk screwing the whole setup and configs! Otherwise I might just do what I have been doing and just manually copy the files/folders I need on the MBP. Do the work and then only just copy this folder back on the MP. Without any full system drive clones.