30,000' for traverse is about 6 miles. If you were in a PLSS state one might assume you were doing the perimeter of 2 sections. If it is in Virginia the shape would be more irregular than a rectangle. Assuming all traverse shots were 500' you would be setting 60 traverse points. You will probably have more. In order to tigthen up such a large traverse, I would suggest 6 sets of GPS checks. In my opinion a GPS set to check for a traverse should be a set of 3 traverse points in series. That gives you a check of 3 coordinates, 2 lengths and 1 angle. Let's assume you will do 6 sets of 3 for 60 traverse points. Assume Pt 1 will be your overall site control and you have only 2 L1 GPS receivers, set on 1 and put the second on 2, then 3, then 2, then 3, moving it to 11, 12, 13, 11,12, 13 and do a third setup on 11 or 12, then one to 21-23, 31-33, 41-43, 51-53 and closing at 2 and 3. The same scheme can be used with RTK. If you have 3 receivers do 1,2 & 3 then move 2 receivers to 11, 12 then 12, 13, then continue to 21, 22 and 22, 23 etc. closing at 2, 3. The object is to make one of each set of 3 with the best skyview as the local control, with more observation time than the other 2, giving it more weight in your LS adjustment. once you have 2 sets you can adjust your traverse in segements to check for blunders, before the traverse is complete and you are well away from the project.
You can reduce the number of sets to 4 if you can do a cross traverse tie. There is no requirement to do exact increments, let your skyview dictate the locations. Say 1, 2 & 4 then 10, 12, 14 but keep them bunched to facilitate checking. Also if you have an internal azimuth point that can be observed from at least 10 scattered locations you can reduce by one set. I would say 1 internal azimuth point is equal to 3 external azimuth points unless you can observe each the externals for along at least 6 points along 1/2 the traverse length. It is a bonus to have azimuth points with recent coordinate values. A CORS within 12 miles can significantly reduce the time of L1 observations and CORS within 60 miles can be considered as control points for static L1/L2 GPS.
With nearby CORS you can make your GPS the control point and GPS your sets as you traverse about making the extra time in the field only for GPS setup and tear down. If you reduce your GPS to pairs instead of sets of 3 you reduce your checks by 1/2 with only a 1/3 reduction in GPS time.
Do not hesitate to make a GPS point with excellent skyview if it is not on your traverse. A GPS point observable from 2 traverse points is as good as a point on line. If the offline point is matched with an online GPS point just tie it in tight with an angle from the backsight as well as the foresight. If you want to minimize the triple sets put them at the fartherest corners with pairs in between. Even a single interspersed GPS point helps but only a little compare to the time advantage and precision of sets.
Paul in PA