Salute!
Plenty of ways for successful do-it-yourself approaches unless the vis/ceiling is like a hundred and a quarter or 200 and a half.
The old ways used DF by tower and your own radio gear ( flew two jets with DF radios, and one was fielded in 1971, plus had better avionics than the original F-16I I flew 8 years later),
The use of the inertial/GPS nav gear plus a good ground map radar makes a non-precision approch fairly easy, even if not practiced. In Thailand during one of the monsoon seasons, the haze was so bad we could not see the field from 1500 feet and 4 or 5 miles. So we used radar and nav gear to align with the rwy for an overhead pattern.
With the HUD in the Sluf and Viper you set tgt elevation, so your tgt "box" ( TD symbol) is very good. Can update position using the radar. So now you can have a symbol at the end of the runway and the correct elevation. We used this to start descending 100 miles out and simply placed our flight path marker over the box. Duhhhh.
So Dan had to enter the position of the field that had not already been entered as a destination. We used to "mark" the ramp or end of rwy at home base to use later, or we could manually enter the coords. So getting an accurate pos for a "strange" field using a flyby nav update seems a good idea. Can use radar to get the TD box there and then refine the coords with the overfly nav update.
The Sluf had that magic map, so you could refine your nav position using radar, then designate your destination on the map to get the TD box and steering.
Gums sends...