For those that may not have both ACKS and the Dwimmermount drafts:
o ACKS page 243 has a Dungeon Wandering Monster Level table which works with a Random Monsters by Level table to randomly generate an encounter for Dungeon Levels 1-6. For example, a Dungeon Level 3 encounter has a 1 in 12 chance of coming from the Monster Level 1 table, a 2 in 12 chance of coming from the Monster Level 2 table, a 6 in 12 chance of coming from the Monster Level 3 table, a 2 in 12 chance of coming from the Monster Level 4 table and a 1 in 12 chance of coming from the Monster Level 5 table.
o Dwimmermount has a Wandering Monster table for each of levels 0, 1, 2A, 2B, 3A, 3B, 4, 5, 6A, 6B, 7, 8 and 9. Level 0’s difficulty is “… comparable to … Levels 5, 6A, or 6B.”
A direct combining of the two approaches is not obvious to me, since Dwimmermount’s levels are not sequentially ordered or necessarily reachable. For example, 2B might have visitors from 3B, but probably not 3A?
Or, one could ignore what connects where and simply let a random encounter be a really random encounter. In which case, maybe I could generically adapt ACKS Dungeon Level 3 possibilities to all of Dwimmermount as:
1 in 12: Two levels shallower wandering monster table
2 in 12: Adjacent or shallower level’s wandering monster table
6 in 12: Current level’s wandering monster table
2 in 12: Adjacent or deeper level’s wandering monster table
1 in 12: Two levels deeper wandering monster table
Use the current level’s wandering monster table when no shallower or deeper level exists.
… which is not too different from Rhynn’s suggestion