I also live around 3 hours away, so I appreciate the necessity to get a good day. Personally, I did my annual visit in the Easter Holidays this year (which I was nervous about), but most queues were no more than about half an hour, with the exception of The Smiler. I'd probably predict a similar case for you. The park doesn't seem too busy lately: no thrill rides are above 35 minutes right now, according to ridetimes, and this is half term! Provided you're there for the full day, you should get everything done without a problem.
I'd recommend the Sunday over the Saturday as this should be quieter, although I understand this may be inconvenient with a 3-hour drive.
Burniel | Great at theme park knowledge, not so great at designing signatures.