yeah parallel compression is good for this but be careful with it as with some tones it can become over bearing in the lower mids/bass.
I've done some live recording where they've only 1 track of guitars- totally forgot about the delay thing!
What I've done with vocals before to simulate double tracking is copy the vocal into a new track, then move that by a few MS, then change the pitch by a matter of cents, pan it to the other side of the main vocal and mix it in to taste. Worked well for demo purposes but I've never tried it on guitar. the amount you delay it by and the no. of cents you change the pitch by vary the severity of the effect so they vary from project to project- just have a play around with them