I travelled 160 miles each way to view the RX 300 I bought. It was well worth the journey. Whenever I travel for a car, I view it as a day out - that way you do not feel pressurised to buy. The downside is that if you travel and the description by the seller is tosh, it can be very annoying. Ask lots of questions - if the answers are not forthcoming then don't bother looking. You will almost certainly have to travel unless you are very patient for one to come up in your area.
Just my thoughts, others may disagree.