Small world, my home village is Wickham near Portsmouth.
Also, Mick mentioned Franz Larch, he is a buddy of mine.
So, if you do stay at Reither Almen, you also get the lift passes thrown in, the passes give you access to nearly every tourist attraction eg Lakes, pools, etc.
It you are interested and I am not on holiday, I know just about every rock and root in this area. Don’t be put off by Mick’s comments, the MTB ing is fantastic, I know plenty of great trails and would gladly show you a few (no uplifts though).
As for driving. Don’t mess about, leave early in the morning, get the tunnel over, then Brussels, Achen, Colognbe, Ffurt, Nuremberg, Munich Austria, arrive in the evening.