I've done this diet before...wake up, drink a protein shake with water instead of milk, a couple of hard boiled eggs, followed by pb/j sandwiches at lunch, and some tuna/chicken at dinner. I'd stay away from the eggs just because of the cholesterol, but tuna and chicken (skinless) are great sources of protein.
If you really want to gain some muscle, you need to eat protein every 2 - 3 hours plus consume approx. 500 excess calories each day. The goal is to shoot for 6 - 7 smaller meals each day. 500 extra cals per day = 3500 per week = 1 lb.
If you eat in the morning at say 7 or 8 AM and then wait till 12 noon to eat again, your body will start breakdown some of your muscle gain if you are working out hard & your metabolism is juiced up pretty high.
peanut butter, tuna, & beef jerky are excellent choices for low cost portable sources of protein. 1 gram of protein per pound of bodyweight is a very good goal to shoot for. It's hard to eat that much protein unless you are supplementing with shakes.