the biggest thing stopping parties from doing epic length campaigns is 1. they meet once a week, it takes YEARS of real-life time to play it out. you need to meet 2 minimum, 3 better, times per week to make real progress 2. Party dissolution. The party falls apart, maybe 3 people are dedicated and its a revolving 4th. Maybe they fight and argue half way through over X and it falls apart 3. Real life upsets, like if somone has a kid be born. Since the games take a long time it is a lot of chances for real life to end the game. Work schedules change, ect. 4. Party Wipe. Party hits level 17, hesistates to cast deathward, and then dies to a vamp-mage finger of death spam. Otherwise you create an adventure and set the victory goal as something only a high level party could do, make it known around level 3-4 what the goal is, then put enough obstacles for 12 or so levels worth of work toward the goal. That puts them at like 17, then you just have 3 levels worth of getting in position to culminate in a final fight after their all 20. Though if what you want is a short-length high-power game it would be better to START at like level 15 as epic heros.
