Great pieces of advice! This is very similar to the system I use for years. This week I just finished construction of May spring travel. The only difference is that we choose a rough destination in advance. When I say rough, I really mean that - our preselected destination was: 'Austria or Southern Germany'. I use booking.com for years, and I have a lot of benefits as a regular user (see hidden offers, have extra discount etc).
Decision car vs plane we base on the calculation of the expenses from viamichelin.com site since it includes gas, amortization of car and road taxes. We compare price from there with the price of cheap flights plus rent and then make a decision ;)
Our construction for 7 nights stay in Salzburg area for 5 people:
- travel by car (gas + tax) - approx 45 EUR per person
- stay in comfy 69 sqm apartment (with kitchen) - 94 EUR per person
And this is a very expensive area. Imagine calculation like this for someplace in Eastern Europe. Our one week stay in Bulgaria a few years ago was 50 eur per person with all expenses, without a food. Complete bargain ;) Very often those travels are cheaper than staying at home since my 'home' expenses are somewhere between 50-100 EUR per week ;)