If your A event is a stage race I think it is totally appropriate to do a full specialty phase including a taper. While you can race in base or build you will still benefit from the fine tuning you get in the specialty phase, even for a stage race.
If it is a B or C event then I would do as others have suggested and roll straight into your stage race off of a base or build program (General build is likely your best bet).
However, lets talk about this as if it were your A event. What I do for this is look at prior year’s of the stage race and try to figure out where I expect the decisive time gaps to be and compare them to my strengths, weaknesses, and limiters.
Some stage races are almost entirely decided in the TT, others by a brutal and punchy crit that sheds half of the field.
If the finishing order in the GC is usually the same as the finishing order in the TT you need to train to maximize your gains there while still ensuring you will be able to finish the other stages appropriately.
If the finishing order in the GC is decided by who makes the selection in the RR then you need to train to ensure you make that selection
So…research your race and the prior results and figure that out first.
Then, compare that to what you view as your limiters. If you’re a strong bike handler and have no concerns about finishing the crit then you can likely skimp on that portion of your fitness. Whereas if you’re like me and don’t enjoy crits you need to make sure you put enough time into that type of training so that you don’t get dropped and ruin your chances
Thus - compare prior years results with your limiters and your strengths and decide where you want to make up your GC position. If you want - post your thoughts on the race as well as your racing profile and I can tell you what I’d recommend.
As an example - if the road race finishes with a decisive 20-30 minute climb that ultimately sorts out the GC (killington or GMSR here in the US) you should train like you would for long efforts while still ensuring you can finish everything else. Sustained power build into Rolling road race or general build into climbing RR would both be viable options (with plenty of other possibilities)