I see plans online that open with a 30-mile week. If that's not you, don't try to start there. You'll get hurt or quit in four weeks, both of which are worse than not starting.
This plan assumes you run 15 to 20 miles a week right now. It's 16 weeks. It won't make you fast. It will get you to the finish.
Weeks 1 through 4: build the base
Three easy runs a week at 30 to 45 minutes. One of those is a hills day, rolling terrain, nothing crazy. The weekend long run starts at 6 miles and bumps by a mile every other week.
No tempo. No speedwork. If you're coming in fresh, your body needs time to adapt to the volume before it adapts to intensity.
Weeks 5 through 10: add the long
Long run grows to 15 miles. Add a fourth easy run. One shorter run should be on actual trail if possible. Cross training is fine on non-run days, especially cycling or easy swimming.
Start doing back-to-back long runs in week 8. Saturday 12, Sunday 6. Then Saturday 14, Sunday 7. This teaches your legs to run tired, which is the whole game.
Weeks 11 through 14: peak
Peak long run is 22 miles. That's enough. You don't need to hit the race distance in training. Ever.
Back-to-back peaks: 20 on Saturday, 10 on Sunday. Hard but survivable.
Weeks 15 and 16: taper
Cut volume by a third, then by half. Keep a short hills run to stay sharp. Eat more than you think you should. Sleep more than you think you need.
Things to not do
Don't add strength in week 12 when you've never lifted. Don't try new shoes in week 15. Don't panic-buy an electrolyte you've never trained with. Repeat what's worked.
I'm happy to look at your plan if you bring it to the store. We do free 20-minute chats on Thursdays.
