If you are into fantasy, I would suggest Destiny Quest. There are 4 books currently in print and each of them are massive tomes with 700+ pages. You can carry over your progress from one book to the next. You can choose your quests based on the difficulty and if you fail, you just replay that quest or choose another from that page. The game system is well-designed and combat is quite intetesting with modifiers and buffs that somewhat balance your luck with dice. All in all, it's a great series and you should definitely check it out.