We play a Greyhawk RMFRP game as do others on this board. You'll likely find a FR game as well.
Since these games have different mechanics from D&D, you might not convert 1:1 and be totally happy.
But you can get to a happy medium.
My old as dirt D&D stuff doesn't go beyond 2.0 and most is 1st ed.
That's as far as I want it to go, so I can't convert from anything higher.
Converting items can be a bit tricky.
My experience is that D&D items are generally more powerful than average RM items.
Most spells cast from items won't be above 10th lvl. It takes an incredibly powerful caster (to work these awesome 20th lvl spells, every day for the entirety of creation. RM casters should be a few levels higher than the spell they are casting just to be confident.
Casting doesn't blow off your head in D&D if you fumble. In fact, there is little to no chance of casting failure as long as your Int is adequate.
Everyone has a system, but IMHO, a 3rd lvl character in RM is a 1st lvl character in D&D. In our games, we start play at 3rd lvl.
Greedy Mage Syndrome:
Magic items with cool abilities must be Attuned. This skill is much easier to learn if you're a Mage. Under RM normal rules, those who Attune to items get experience. But only the Mage can really afford to buy Ranks in Attunement...
Also, most of the Items found by PC's were of Essence. Now there is little to no chance for the Thief who happened to pick Channeling as his realm to Attune to treasure.
This forced me to go through and ask, who made item "x", why and what was their realm of power? This helps flesh out the campaign but does take more work. There are a ton of 2-bit magic items in most D&D modules. Go through and make a history and Realm for each one. It's going to matter when your players start casting spells to discern use. Maybe the Mage can only cast Detect Essence and the Mystic can only Detect Power... They might never find out the powers of a Holy Hand Grenade of Antioch.
Treasure:
Assume a silver standard. Make everything the module states in "gold pieces" to be in silver... and then maybe cut them in half. Greedy players whine but bored rich characters are spoiled.
Creatures:
The vargouille (Penanggalan?) sure looks like a disembodied head from Creatures & Monsters. Bite, nausea, etc.
Is there something specific that you want to convert?
My game may be totally different from yours, but I'll help if I can.
