It's certainly doable to keep France out. It's extremely hard to keep France out and have the colonists still win independence (which seems to be what you are asking for) for two reasons:
1) The obvious one that without France, the US is going to find it tough to win.
2) Once the US manages to start look like they are winning (obviously needed for the US to win), it becomes increasingly difficult for France to avoid the temptation of joining in to pile on.
Really, the only way I can see it happening is if the colonists win so fast that the French don't have time to intervene, which is a very tall order (especially since independence wasn't a goal until mid-1776, so you can't have e.g. a storm prevent the evacuation of Boston and force its surrender with British garrison intact, which is probably the easiest "quick" major victory).
That said, I'm not sure no French intervention will make a post-war US crack-up more likely; indeed, a wildly successful intervention (such that the US gets Canada and Bermuda, which were basically the maximum gains the French offered the Americans in the event of a complete victory) might lead to the US becoming even more unstable (in particular, Catholic, French-speaking Quebec with its claims on the Old Northwest is going to present a massive political problem for Protestant, English-speaking Americans, especially since the absence of British Canada means that a unifying threat is removed).
Indeed, that would probably be an easier scenario for a broken United States: a massive Franco-Spanish naval victory over the British allows the planned invasion of the British Isles to go forward, and as a result, the Allies get to essentially dictate terms to an occupied London. The British are essentially removed from North America and the US finds itself with many states with divergent interests and no real unifying features (with even religion, culture and language varying between Quebec and the rest).