Hi JMoo
I know there are a lot of Garlands Records at Carlisle Archive Centre, I made the boxes to house the volumes and it took months. From memory, the time span you are talking about is particularly rich in records.
Photo copying is a sort of "rule of thumb". If the records are robust and have not deteriorated, then there is usually no problem but if they are fragile they can only be photographed and then only in natural light
I have found that anything over 1.5 megapixels gives quite acceptable results for transcribing documents and/or printing off on your own printer. However if you want something to frame and put on the wall, I would suggest you look at a camera with 4mp plus. The £5 daily fee lets you take as many snaps as you want so if I were you, I wouldn't try and read everything you come across, just snap it and delete what you don't want when you get home.
If you PM me with the name and dates, I will have a quick look for you tomorrow.