periodisation, no point going long and fast, get one right then the other.
3 weeks of very long rides, say 80 miles, as often as you can (saturday and sunday?) as slow as you can, if granies/kids are overtaking you youve got the pace about right. Mid week some short rides 20miles or so, can be at an average pace, just dont push yourself, thats not the point.
1 week off, just some short evening rides to keep things ticking over.
3 weeks of hard and fast riding, every 3-4 days you should go out for 1.5 hours (half hour warm up, half hour training, half hour cool down) or so and ride as hard as you can, go a bit faster, then take a break for a few min, the go fast, etc etc. If you dont want to die at the end it wasnt hard enough. Keep one big ride per week at the weekend, but keep it slow.
Take a week off, some short rides, eat lots of carbs
Then got for it.