Well, for where I-42 has been designated for now, I have created a very preliminary exit list for the corridor segments that are freeways, interstate standard or not, at this time. Info largely taken from US 70 in NC Wikipedia exit list. The listing is at:
http://gribblenation.net/ncfutints/i42exits.html
A couple of notes to assist you with your exit list:
Exit 409 (I-42 Exit 92) is
Clarks Road (aka SR 1225)
The US-17 Bypass exit is Exit 410, not sure where Wiki got 411 from.
The NC-43 exit is 411, not sure where Wiki got 412 from.
There are several unnumbered exits in Craven County, all original exits from when the freeway was built-from west to east:
Unnumbered (should be US-70 Exit 400) NC-41 South//Trenton Highway (we locals call it the Cove City Exit).
Unnumbered (should be US-70 Exit 408) Tuscarora-Rhems Road (aka SR 1224)
Unnumbered (should be US-70 Exit 414) S. Glenburnie Road.Unnumbered (should be US-70 Exit 415) US-17 Business South//Dr Martin Luther King Jr Blvd.
One thing to keep in mind, too, when judging I-42 mileage is that I-42 won't using US-70's mainline the entire distance. The Goldsboro Bypass adds 1.3 miles to the distance from New Bern to I-40, and there is not yet a way to tell how much of a difference the as yet undesigned Kinston Bypass will make.
I have the distance between the MLK exit in New Bern to the exit ramp to merge to I-40 using the new Goldsboro Bypass measured as 98.6 miles (3 trips now, measured with a Garmin Nuvi-2689), it was 97.3 miles using the mainline through Goldsboro.