>how hard is it to put in?  I've no tools beyond socket set and wrenches
>at present - should I try do-it-myself?

You will need a sturdy set of jackstands and a good floor jack, and the correct tool for the CV bolts (some are allen, some are tri-square.
>
>One of the CVs needs replacing too -- is it easier to do the CV and the
>tranny at the same time?

Since the inner CVs must be disconnected from the tranny to remove it, yes, it's easier to do at the same time.

This is certainly a viable do-it-yourself job, but you will need to be careful and have a helper. (I'm sure someone out there has changed an engine or transmission alone, with nothing but the tire changing jack and and a pair of vice grips, but it's not the recommended way! :-) )

Bill