I agree: three game activities and let the remote figure out the switching. This is assuming that switching is reliable for you, though.

I got an LVM-37W1 a few days ago. When I set up my Harmony (H768), it was very clever about using state variables to decide whether it had to hit DVI (for example) to jump to the right input. If the TV missed an input switch, though, the Help menu was completely ineffective, as it never attempted to fix the input when I said "No, the TV is not on the right input". This was not satisfactory for my family.

I don't know what the 42w2's inputs look like, but fortunately for me, the 37w1's remote has buttons for "next input" and "previous input", and I determined experimentally that I could get to any input in one keypress (VGA, AV, S-VIDEO) or two keypresses (VGA+NEXT INPUT, AV+PREV INPUT, etc.). So I just programmed the video switching with sequences of AV/S-VIDEO/VGA followed by NEXT/PREV INPUT. After getting the delays (2000/200/1200/2200) and repeats (2) set correctly, it now switches quite reliably. If not, Help always does the right thing, because it effectively has discrete key sequences to choose the inputs.