The randomisation chart on the right should help anyone grab a random Isle of the Unknown tile whilst sitting at the table.
Dropping a d4 on the map can do the same thing, but mine always end up in the wrong place.
Roll a d10, a d3 and a d12.
The d10 gives you the table to use. The d3 gives you the column and the d12 gives you the row.
I may pretty it up a bit later to make it more usable but the data is there for anyone if they want to.
The hard work was done by my friend the maths guy.