BookBarbarian
Expert Long Rester
I do something very similar. I have a chart somewhere where where I took the expected xp per average adventuring day, and compared it to how much it takes to level. It's around 1 day to level up at very low levels then moves up to just over 3 days at mid-level, to back around 2 days at high levels. Now I just keep track of how many adventuring days we've had since the last level up to determine the next time we level up.