Last time, I was setting my overall parameters for the design of this mod. I determined that I would need to cut or combine encounters to fit the mod in a reasonable amount of play time. Today, I'm using going through the mod in detail to determine which encounters to convert directly, which encounters to combine and which encounters to cut.
To do this, I printed out the map of the dungeon and made brief notes on each room about what it contained. That gives me a quick, 'at-a-glance' overview of the mod without me flipping back and forth through the whole thing. The first thing I noticed when I did this is that there are way more encounters in the mod than I thought! From the description and my brief reading, I was planning on having to cut from 18 encounters down to 12 or 14. My new count has upwards of 24 encounters! What to do?
Further analysis of the map shows that there are multiple paths through the dungeon, and it is possible for a clever party to miss entire sections of it. That will let me include a few extra encounters, because a party won't necessarily face all of them. I'll say that taking the multiple paths into account will allow me to include about 18 total encounters, hoping that a party will only encounter 3/4 of them.
That still leaves me with a few too many encounters. To make the first round of cuts, I'm going to use some tricks I learned playing a conversion of the original Ravenloft adventure a few weeks ago. The DM had converted some of the single monster encounters, which in earlier versions of D&D would have represented a legitimate challenge for a party, into an effect more like a trap. For example where the original module called for a banshee to appear, instead of running an entire fight against a single banshee, the banshee made a single wailing attack against us all and then disappeared back into the mists. This saved time at the table, maintained the fast pace of the original, and still had an impact on the PCs. There are a few encounters of this type in A1, so I'll convert them to an effect like a trap (some ideas: a group of archers fires a volley then retreats to another position, a group of monsters rush the party and deal some damage even as they are cut down).
Still a few encounters over, I turn next to combining encounters. In earlier editions of the game, encounters with a handful of weak enemies were common. The 4e equivalent would be to happen upon a group of minions. In 4e, running all of those individual fights would take too long, and not be interesting enough to be worth spending time on at the table. Without giving too much away, I can say that there are several areas in the original mod that list encounter statistics for rooms like this that are very close together, and that for my purposes I will treat these thematically linked mini-encounters together into a larger encounter. Basically, I will use a suite of rooms as the area instead of a single room.
That brings me down to my magic number. Now I'll need to convert the remaining encounters to the new rules and away we go. Stay tuned.