Why not just draw a line on a map, take off, fly your heading, pick a point a few miles away on track, adjust your heading to keep you going towards that point, then do the same again with another point once you've passed it? After your initial calculation with the computer the wind is changing all the time on a long cross-country, so this is effectively what you end up doing anyway, especially if you end up dodging round a shower or something.
As for ground speed, most sane people with their feet in modern reality read that off their GPS, don't they? I do.
QDM