Hi mr jones -
<<"Hey guys, yep dates were mixed up on the post. Working nights is leaving my brain a bit fried...
So I land in Basel on the afternoon of the 19th (Tuesday), catch an early train to Wengen from Basel on the 20th (Wednesday), stay in Wengen from the 20th until Friday the 22nd, then fly out Friday afternoon. Planning to do maybe the Schilthorn and/or Trummelbach falls on the 20th and Jungraujoch on the 21st. ">>
Pretty sure that you mean June, while the OP meant July.
There is a world of difference.
The high trails will be open when he is there, and the tourists will be arriving
When you are there, if you are lucky, the high trails will barely have opened. It's the tail end of Winter at those altitudes. June 15th is the rule of thumb for trails at 2000+meters opening for hjikers...in an average year.. Lots of snow this past winter, so.....maybe later.
Many but not all hotels and restaurants take a break in May +/- and open up in June at varying times.
So, if taking a walk means along the floor of the Lauterbrunnen Valley , or Grütschalp to Mürren, no problem.
<<"The Friday is basically free for a short hike or quiet morning walk before catching a train back to Basel to meet my flight out.">>
However,it is unlikely that you'll be able to take this easy and wonderful walk:
A few of my images are attached. Perhaps they'll encourage you to come back again. ;-)
Still, you'll have a relatively un-touristed time, which can be relaxing. Hope the weather is sunny.