cant say for Mark, but as with 727 i use radio navigation. 707 gives one more nav - Doppler. I dont have INS yet.

So, for typical flight. You take assigned SID, set radios and (usualy it is necessary) make some extra calculations how not to miss intersections.
After takeoff you fly by hand using radio navigation. As you exit SID, intercept required radial. Your flightplan should indicate it. Look pic.

Say you fly Portland to Honolulu. You gona fly above the ocean most of the time. You plan to use radio navigation to coastal beacon ONP VOR. and from that point you will use Doppler Nav.

Exit KPDX SID, and intercept radial 209 of ONP VOR. as you established on course, program Doppler, but dont engage it yet.

Set on Doppler control unit
LEG A ONP VOR- HEMLO waypoint: Heading 220 Distance 136.5
Leg B HEMLO waypoint - HOLOT waypoint Heading 221 Distance 95.6

As you flu over the ONP VOR, engage Doppler NAV and set AP mode to NAV.

You will fly entire route be Doppler NAV, until you arrive inrange of CKH VOR. Then intercept radial 219 and prepare for STAR to PHNL.

Thats the basic idea. This example taken from standard FSX flight planner generated plan for KPDX PHNL, using  high altitude airways route.

Thats fun! same for desert flying

I fly either an INS plan or I will save a plan made inFSC9 and load and use that. For INS plans, I use the free Plan Converter (http://darkc.no-ip.org/trac/planconverter) to convert the FSX flight plan into AWC files that splits them up and creates a text file that tells you when to load each plan (i.e. KBFI to PHNL.1, KBFI to PHNL.2 etc...). See attached image.

The downside to INS is that the flight plan must be made and converted into AWC before I start FSX. When I forget to do that, I usually load the plan as an FS Flight Planner plan and fly it that way.

Mark