I'm a customer, so this will be far short of a true ThinkGeo reponse, but teaching is the best way of learning, so here goes.
We use lots of projection stuff. The easiest that I have found is to use the EPSG Code integers as the SRID parameters on the Proj4Projection. SRID = Spatial Reference ID.
I'm assuming when you say UTM Zone 14, that you really mean UTM Zone 14 North, based upon the NAD 83 datum (North American datum of 1983). This is the most common format for projected data in North America. Note that you may bump into NAD27 data (North Amerian Datum of 1927), which has a different set of EPSG codes.
So, the EPSG code for a NAD83 UTM projection is 26900 + the UTM Zone Number. There are 60 zones, 6 degrees wide covering the world. I think NAD83 is defined for zones 7 through 18 or something like that...
The way to find your zone from a longitude is: zone = (int)((lon + 180.0) / 6.0) + 1;
So, UTM Zone 14 North is data from 96 to 102 degrees West, North of the equator, and is EPSGCode = 26914.
The constructor on the ProjNet takes two SRID parameters (as one of the options). The internal projection, and the external projection. Internal means "what is the native projection of my data". External means "what do I want to convert to". Normal Lon/Lat data is expressed in WGS84 Geodetic datum, and the EPSGCode for it is 4326. So, your constructor is:
Proj4Projection p = new Proj4Projection(4326, 26914)
If you want to convert native Lon/Lat to projected. Of course, it is the reverse if you want to to "unproject" your projected data to the lon/lat of the WorldMapKit.
I think you are right. You will typically want to project your WorkMapKit data to zone 14. And, yes, when you get "world" tracking coordinates, etc, they will be projected. If you want to convert those projected coordinates back to lon/lat, you just call:
BaseShape projectedShape = projection.ConvertToInternal(trackedShape).
We provided a modified copy of the world map kit to the support team for inclusion on the code project page. It was a single layer that encapsulated the entire world map kit as a multi layer derivation. It had a projection property on it, and would iterate through hundreds of world map kit layers setting the projection. I had support for other things, too. I don't think it ever got posted, but you might ask support for it.
Hope this helps, rather than muddles.