Do you have a planisphere? Mike sells them in the IIS shop (last time I looked
). They are a cheap simple tool - turn the disc to match your date and time and the planisphere will show you what is visible where in the sky. You will still need your star charts to find the deepsky stuff, but the planisphere will help to to identify and find the brighter stars. Find a bright star near where you want to go and starhop the rest.
Glen's advice about 7x50 binos is good too. That's how I started and its a great way to learn to find your way around and you don't need a mount like you will with bigger binos. You will always use the 7x50s
.
By the sounds of it, I would warn you to be very wary of a GOTO Mak/Cass. For the goto to work with minimal fuss, you need to have it polar aligned. That means you have to be prepared to for all the setup and strip down fiddling about, collimation (because it will shift when you transport the scope) as well as polar aligning.
IMO you'd be better to stick with the 12" dob, learn the sky with the planisphere and 7x50s, and learn to collimate it
... the views will be so much better!
Al.