TCAS is a great aid if you have it. Several units available now for light GA aircraft. The see/avoid works (for the most part) - there have been a few midairs over the years at airports with both tower and not, due I think radio position misunderstanding or no radio. I flew jets (without TCAS) into many uncontrolled airports with several planes in circuit area, it can be a little tense, you sure need to keep your heads up. Slow guys will usually help you out. In the US, if you're an IFR in VMC, you have the same responsibilty to avoid traffic as a VFR guy.