[veloran]

I have played with an 17" dob alot and from experience I have to say "put the springs back in!".
telescopes work on exact alignment (columation) and without the stabiliser springs the tube will be taking more vibration and shock then is good for the secondary mirror. In a dob or basic newtonian the secondary mirror out of columation to the primary is just death.
If you're a small lady then having to columate a 12".. it's not going to be fun at all as you have to be extremely precise..

A simple wheeled trolley will do the trick for movement... put him on one of those and 'slowly' push it where you want to go.
OR build a trundle system..
it's simply two long poles with wheels at the end.. put a bracket on each side of the mount that they can slot into from underneath and you now have a dob-Wheelbarrow which makes everything MUCH easier due to mechanical advantage (the weight is decreased by the fulcrum so it is lighter to move).

a 12" dob is not really a newbie level scope and needs special teatment.

1) If you really want to leave him outside a small shed and not just a tarp is a good start.. treat dobbie good and he'll treat you good (plus with a few golf-balls set in the roofs runners you can turn a shed into a moving roofed observing hut
2) telescopes don't like heat but need cold.. always keep it in mind when thinking location
3) always park him at zenith and always put on his tube cap.. moisture and dust will strip your mirrors coating (bigger the mirror bigger the cost to fix)
4) As a newbie you'll find tracking an object a lesson in humility with such a large dob. learn to track an exact section of the moon for 5 mins then bright star or planet for 5 mins.. if you can do that then start toying with the idea of photography with a dob.