I'm considering getting a MicroTrack for use with a plant mic since it's easy to conceal. Does anyone know the correct adapter to get an XLR mic into the 1/4" inputs?

Would the Hosa GXP-143 work?

Yes that adapter should work, but you might want to consider a cabled version. with the size of the adapter and the size of the XLR that plugs into it you are going to put a lot of strain on the input jack, not to mention if the mic inputs are close together you may not be able to plug in 2 of these side by side, perhaps get a short 10" cable with the proper connectors that way you can still use a standard XLR mic cable, and you won't be putting the strain on the recorder itself. one of the dangers of having phantom power in a TRS is shorting out during insertion or removal of the connector, so be carefull to either disable Phantom or turn off unit during insertion or removal of the TRS.

Hope this helps

Oh, excellent advice Gerry -- thanks!