I have the opposite problem, ahahah. I'm trying to get more Investigation tunnels but they keep on just plowing through without coming across one. I'm not really sure what the chances are but wonder if there's anything really worth getting from those investigation tunnels. So far, every sim I've sent down has come up extra crispy except for one and he didn't bring anything useful back.
I kinda' got ticked off at the travel tunnels though, the travel time is way too long in my opinion and should be at least half as long to be even remotely beneficial over a moderately fast car even if the holes are on exact opposite sides of town (Might be incredibly useful in the travel locations though not being cars around and all that, although I haven't tried just yet).
I wonder how many time travel/underground adventure exclusive outfits there are out there?
My current main female sim has got a medieval dress and hat as well as a nice sleek futuristic body suit from time traveling that I like quite a bit. ^_^ The ghosts in the Ghost Hunting career seem to wear two variations of historic clothes for each gender so there should be at least that many for going to the Past, but for the Future, that's still a mystery to me.