I know your posts are quite old but if anyone still is looking for these I second doing Reavers of Harkenwold. The problem though is straight conversion 4e to 5 is a real problem and it's not 4e's fault. The MM takes no consideration for "level" of monster but instead returned CR, which I hate. 4e used different levels and roles for enemies whereas 5e its just a CR and you have mess with everything to make it more powerful, or give better roles - making them as regular PCs and flavor the monster race actually works far better than figuring out the dizzy CR. 4e to 5e takes a LOT of preparation. NOTE: keep the heavy 4e stats or else your casters will just lock them in place before they can do anything and if that happens all the time then its no challenge for players.
So in order to convert 4e ones you have to re-tool or just do the theme as someone mentioned earlier. Even then the MM is severely lacking. Frankly it is the worst product WoTC has made this time around. There's good MM's from 3rd parties if you don't mind digital for all that (I do not).
Without almost a total re-write for 5e, fudging it for a 5e group will steamroll over the encounter yawning as they go. TIP: use traps especially in what I think is the best encounter, the sanctuary. Those floor traps between rooms can be wicked. I have note cards of reworked stats of everything in it. I've found the beta Encounter Builder to be subpar so if anyone wants these let me know and I'll send a link to them.
