All your manual labor is another form of cross training!!!
Yeah... my weight is down a bit from all the totin', squatting, etc.
But I am sore all of the time. Lower back mostly as I've been ignoring my core for months... many months.
Remember, many of those old time runners (esp. Europeans) were manual laborers too. Hard to imagine.
The runner that astounds me the most is/was Glenn Cunningham. The man ran 10 miles a week OR less and probably could have broken 4 minutes if you gave him a decent pair of shoes and he ran on a good track...without any additional training, just take him at his best and add those two factors.
Most of his running if not all was at absolute full power and some of the manual labor he did was incredible...he ran on the power of this limited speed work and strength.
I'm weaker than ever myself. I do average of 45 minutes of different exercises to try to cover every past strain and injury to my legs from my hips to my feet. Some of this is core stuff. I also try to stretch my calves some.