Snap to anywhere on line

I need to snap to guide lines but the only snap I can get is to the endpoint, which results in some very diagonal lines. I actually have ortho turned on because I need only 90 degree angles. Sometimes I need to move an entire line and I would like it perfectly lined up to the guideline. The line being moved is part of a polyline.

I sometimes do need to start or end at an endpoint but how do I do that then also snap to just anywhere on the guideline while maintinaing a 90 degree angle?