Im training for a marathon and wondering how far apart other people space their really long runs......like 18,19 and 20 mile runs. I gave myself some extra weeks in anticipation of fatigue or injury, but so far so good. Now Im finding myself a little ahead of schedule. I was planning on doing 20 slow miles this weekend, only doing 10-12 next weekend, then the following weekend trying for 22. I know many training plans dont go over 20 miles, but I really need the extra distance for my own confidence. Is 2 weeks long enough to recover from a 20 mile run that is run slow with walk breaks? Also, is ok to have my longest run 4 weeks before the race or is 3 better. I dont want to feel rusty on race day......or too tired.