I use a lot of D&D modules in my rolemaster campaigns. I tend to convert by rule of thumb and not a set formula. I also change some of the monsters encountered because they are much deadlier in Rolemaster. Practically every D&D module has a dragon in it. Even first level modules. D&D dragons are merely big lizards with wings and bad breath. A Rolemaster dragon truly strikes fear into the hearts of characters. It is something to be experienced only at the pinnacle of your adventuring career (probably the end of it as well
) Obviously, if I replaced the D&D dragons with Rolemaster dragons no one would survive. So I replace them with lesser monsters that fit the story and yet the party should still be challenged by. Rolemaster is just too deadly to do a straight conversion.
I also lower the monster counts somewhat because it is nothing for a single D&D encounter to contain many many monsters. This is because if you are a high enough level most of those monsters will perpetually miss you. 20 Orcs in a room will hit a 10th level D&D character maybe 5-15% of the time for some small damage. Any one of those same Orcs in a Rolemaster encounter has the potential to kill a character with one hit. Keeping this in mind I reduce monster hoard counts by at least half. I want to make it possible to die but not all out probable to die.
I have also found if you multiply the level of the encounter (CR) by 1.5 it is roughly the average level the rolemaster characters should be.
Also, DC * 5 roughly translates to the skill percent you need on a skill roll.
locked chest DC 20 would = a lockpick roll manuever of 100+
You can map this to the Rolemaster scale of routine through absurd without much hassle.