Hi, a bit old this thread, by the way...to be safe it´s a good idea to replace the timing belt every 45,000-50,000 miles, but how many years? I´m seeing a 156 V6 for sale, the timing was replaced 15,000 miles and 6 years ago. The car is 300 miles from home do I would have to drive back that distance.
unless the engine has been standing for ages you should be fine to drive the 300 miles home and use the car for a bit.
You can loosen the belt cover and make sure the belt is running nicely on the cam pulleys and not sliding off towards the covers which can happen if the tensioner starts to disintegrate.
15000 miles isn't much, so the belt should be fine for now, unless it has been left standing for yonks.
However, if it was me I would get the belt changed soon. And if there is no history with the car, then also all the timing belt roller bearings. These can seem beefy and strong, but they do fail. Then also, the water pump, and also the auxillery belt, tensioner and pulleys. And, make sure the aux crankshaft pulley is still running straight. In Britain at least, the salt water can get in the seal, and rust causes the pulley to go out of shape.
I have just had all this work done on my 166 3.0. I have the full service history for the car. It has done 164,000 miles on the original aux belt tensioner and bearings...(they were shot, as was the crank pulley). The camshafts are still as new though.
Also, these engines can suffer from belts done on the quick (I.e only locking the front two camshafts, leaving stripped threads in the block (waterpump or rocker covers) , re-using rocker cover gaskets again and again, only changing front bank spark plugs etc...) .
It is one of those things, I would use the car for a while, (as long as the belt looks good from a visual and audible check) and if you decide after a few months you love it and will keep it, then get everything done properly. There will be other issues to sort too...anything from clutches to suspension arms/antiroll bar bushes...though in Spain, maybe not rust?