Questions before I try a new Rom

[erisp]

Ok

So far I have:

Rooted
Installed Droid 2 Bootstrapper Recovery
I went into the recovery menu and did a Full Backup
In titanium Pro I backed up All user apps & system data

I plan on trying a rom since this will be the first time I wanted to know how to get back to my phones current state.

I'm curious on steps I need to take in order to go back to my original Rom? and apps. Basically a perfect copy before I changed.

Also for example can I go from Gummyjar to say Cyanogenmod?

[Abe21599]

install a new rom:
download rom
boot into bootstrap
wipe data & cache
install from zip
reboot
install titanium from market and proceed to restore apps

Back to original (if you dont like what you installed):
boot into bootstrap
wipe data & cache
restore (still in bootstrap) and choose the backup file you made

and yes u can go between roms all you want but you need to wipe data and cache when switching roms; otherwise, itll cause issues