I am doing a 77 mile charity ride in April and have been out cycling (weather permitting) and when that has happened have used a cycle machine. I want to up my game and would like advice please? In addition can you recommend any books please.
The best thing to do is just ride your bike everywhere that you can. Commute, do the shopping, run errands, etc. There's an older thread answering a similar question with some links to training guides and things....
Have a look at Fitness Cycling by Carmichael and Burke for training plan suggestions and perhaps Long Distance Cycling by Burke and Pavelka.
There is nothing like riding outside on a real bike - stationary trainers do not improve your bike handling, hazard perception nor do they help you optimise bike fit and comfort. I may be in a minority of one, but sold my stationary trainer as I realised I preferred to ride in the rain than stare at a wall.