Here's a few suggestions to sweeten the experience (see photographs below): If you feel like you must actually go onto the narrow winding medieval streets and stairs of the mount itself and visit the labyrinthine bowels of the Abby itself, then park where they will herd you and take the horse draw conveyance up to the mount. Because it will cost you 5 Euros per person the line is hugely shorter than the free shuttle and it takes an interesting circuitous route where you can see up close the new dam to control the tidewater and various interesting angles on the exterior of the mount.
My first suggestion, however, would be to take a different approach altogether. Unless you find crushing mobs appealing, don't go onto the mount at all. There is a beautiful drive from the Norman villages leading to the mount where you will enjoy spectacular views, and see local farms and farming, and a windmill or too (not the si-fi horrors of quixotic-reversal alternative energy fame). And you may very likely enjoy stopping and watching artists paint this stunning scene--from outside the walls. There are a number of local restaurants where you can order Moule frites and a glass of Normandy cidre and have a peaceful lunch gazing out the window at the mount (reminding yourself of what it would feel like to be a live gasping sardine moving in shoulder to shoulder convoy with a vast throng of other sardines also wondering why they didn't take the advice of this blog and view in tranquility from the shore).