Before beginning, make sure to install an official global shape model. This will ensure that the DTM generated will be tied to the official coordinate system.
Use JMars for the Moon (or some other appropriate program) to determine which images will be used to build the DTM. Use the calibrated images. Ex. M102165049LC
Use processLRO-orig.f to ingest the images. The SPICE kernels for each image will need to be added to LRO/PROCESS_IMG.IN.
In JRW's experience, the SPICE kernels are poor enough that the image position/pointing will need to be updated before building the DTM. Perhaps this step will not be needed if using an official global shape model. Nonetheless, it would be good to find a low emission low resolution image (such as a WAC image), and align all the images to it. A low emission image is key to minimize projection problems; for LRO, there should be WAC images with only a few degrees emission angle. All the images should then be aligned to this image using "x.register".
After this step, all the normal SPC procedures can be used. However, be careful with using lots of AUTOREGISTER and GEOMETRY Opt 2. Always make a backup before doing either, and try to minimize the number of times you run these programs. Since we are now aligning the images before generating the DTM, frequently updating the position/pointing is probably okay, but in the past JRW has gotten into trouble by using these programs too much.