I just came through Florida, Alabama, Mississippi and Louisiana with all their love bugs. I didn't have anything else with me, so I got most of the bugs off with sprayed soapy water, a rag and a lot of elbow grease at the first overnight stop.
After the front end dried, I sprayed it with a little WD40 (of course, not the windshield) and left it wet. On my next stop, a plastic paint/ice scraper with a spray bottle of soapy water took them off in short order. It worked so well, I reapplied the WD40 and proceeded down the road.
For the windshield, the soapy water and plastic scraper got the job done with, of course, a generous helping of the invaluagle elbow grease.