Cool season plants all summer??

Getting my plan together for this growing season (my first SFG) and trying to figure out what I can continue to grow throughout the summer. My early spring plantings are as follows:

Peas
Spinach
Potatoes
Cauliflower
Broccoli
Onions
Lettuce
Carrots 
Spinach

Many of the above will be harvested and replaced with my warm season plants like tomatoes, beans, etc. But I'd like to continue planting and harvesting my carrots and lettuce throughout the summer, but not sure if they will tolerate the heat? I'm in Eastern West Virginia, Zone 6B. I'd also like to continue my spinach, but I'm almost positive they won't handle the summer heat. If I can successfully grow these throughout the summer months I'll plan to stagger my planting times so I'll have sort of a continual harvest. But if they won't survive the summer months, I'll plant and harvest all at once.

Any tips/tricks to growing things like lettuce, carrots and spinach all throughout the summer? Should I plan to shade netting during the hotter months?

I have managed to grow cooler season crops in the summer, but putting them in shadier places during the hot times....
I have a tree in the middle of my yard and I plant things on the north side in the summer, also the north side of my house.

I keep planting Carrots all summer, just seems they need more water later on

Malabar spinach (not a true spinach) should last through the summer.
Lettuce - if you can shade it (under a tree, etc) will not bolt as rapidly but it will bolt sooner or later.
Carrots - I left these in garden all summer and finally pulled them in Feb.  Not normal but that is the way it worked out.

I actually usually leave my carrots in ground until winter. They are supposed to be sweeter after the first frost.
Sometimes it gets hard to dig them up though, depending on how far down the ground is frozen