If we have a cool summer (like last year) my spring-planted peas wanted to go all season. You can definitely plant a fall crop by direct-sowing them, you shouldn't need to start them inside.
Tomatoes are a constant struggle in our area; I have several small green fruit but those are on tomato plants I started from seed in February and have spent way too much time caring for.
It seems rare to get any tomatoes before July around here without extreme measures. Last year was awful and I only got maybe 10 tomatoes out of 30 plants.
I wouldn't give up on them, though, it is still early and supposedly we're going to have a decent summer this year.
Potatoes I planted back in late March - they can take cool weather just fine. I'm not sure if you could still get away with planting them now; maybe an early variety would do well? We don't have particularly hot summers so you may be able to get away with it.
This year (after being scarred from last summer) I focused slightly more on cooler weather crops like peas, potatoes, onions, garlic and salad greens to hopefully have more success. I still another 30 tomato plants out of stubborn determination to get homemade salsa and sauces, though.