Re: VH/VH SS.4 France Advice
Like Boogie Knight said, the HRE's biggest thread can usually be neutralised with an alliance bloc. I generally ally Denmark, Poland and Venice, they're overall safe options as you generally won't encounter them early in game. They all border the HRE though and if your relations with these nations is good they can be helpfull against the HRE, even if not all decide to go to war with them.
For Genoa, try capturing Marseille, it will make it easier to block Genoese armies and gets you some money upon capture. You may have to scrape together an army but it does decrease the Genoese threat and brings in a few thousand florins to invest in your economy.
I've personally never had much trouble with England. If you kick them off the continent they'll get pretty predictive, landing a stack near Caen every few turns so either leave an army to kick them back into the sea there or build a navy to feed the fish. Alternatively hope for the Norwegians or Danes to invade them or an early incarnation of William Wallace.
The HRE is probably more work as there's not really a way to create a bottleneck that allows you to stop their armies. You'd have to break them or hope they fall out of favour with the Pope.