I stated with clipless Look 166 in the 1980s. They were a revelation over using leather strap and metal cages. I upgraded to better Looks when they became available. I sort of dealt with the cleat replacement (about 2 pair a year). In 1999 I bought some Speedplay X2's. I figured that the cost of them was less than I had paid for Look cleats at $15 a pair x 2 x the number of years I had used them. I still use X2 on both road bikes. Full float is fine but I also don't have knee issues. I use my SPD mountain pedals on one road bike where I know I will be walking sometimes. I don't feel any problems with out the X2 float and don't find any loss in "performance" over the road dedicated X2. So, for the OP, I would say go with some mountain bike SPD pedals and good shoes, Sidi, etc. You are not racing so the slightly more heavy SPDs will be not noticeable.