My advice in post 2 of this thread (photo place = Clarens) does not work, because of one thing I didn't think of: what to do with your luggage. In fact, your concern will be difficult to satisfy:
- A budget trip in Switzerland (that alone is difficult to achieve, although not fully impossible);
- With your "old" parents (well, I'm 70 myself and still do quite a lot of challenging hiking, but I understand it is not the case of all people my age);
- You travel from overseas to three countries, so you are likely to have bulky luggage.
I'll tell you my own personal advice: take the estimated budget you have calculated for this trip, and do something very nice for your parents in your own country. I'm sure you could do something beautiful, and imagine how less stressful it would be for your parents and your wife! I assume you are surprized, but really consider it!
But maybe your parents always dreamt of visiting Switzerland. So I have a few additional questions:
A. Have you been to Switzerland before, or western Europe?
B. What kind of luggage do you plan to have? Is it possible to pack in such a way that your parents' essential items for 2-3 days are in the suitcases of yourself and your wife, while their own luggage is checked in for a further destination (such as check-in in Geneva upon arrival from Paris to be rail-freighted to Brig just before leaving Switzerland for Italy?)
C. How far can your parents walk (on paved ways, with no luggage to carry)? That's because the cablecar stations I know are at some distance from railway stations.
D. A car rental is in the range of CHF 120 to 150 per day plus petrol, would that suit your budget?
E. Budget travellers use Youth Hostel (no age restriction in spite of the name) where people sleep 4 in a room, and use a bathroom on the floor. Would that be acceptable?
There are green pastures and snowy mountains in France and in Italy. In fact, the highest peak in Western Europe, Mount Blanc, is on the French/Italian border, outside Switzerland. Did you consider finding your postcard place in one of these countries? They are considerably less costly.
Sorry about that. Now read again my entire message.
I wish you, your wife and your parents a relaxed time full of smiles.