The satisfaction of raising a bountiful crop of delicious, fully ripe tomatoes can't be beat, and as experienced gardeners will tell you, so much depends upon the weather. Many long-time gardeners use Mother's Day as the signal to plant your tomatoes outdoors. In the Pacific NW, that's not a bad rule of thumb, but as long as you can protect your starts from unexpected drops in temperatures, planting earlier is usually okay.
Another guideline is to plant the seedlings deep, leaving only two sets of leaves above ground, even if it means stripping off bottom leaves on a particularly leggy start, or actually laying it at an angle with just two sets of leaves above ground. All the little hairs along the stem will become roots, providing that much more water and nourishment to the plant. You'll also want to install your support, be it a cage, trellis, or some other structure, at the time of transplanting so the roots aren't damaged later on. Planting a tomato with no support will only cause heartache unless you're planting a tomato in a hanging basket. Growers have had varying success with this tactic, depending upon the actual container and the variety of tomato.
Moskvich, which translates to "inhabitant of Moscow," is adapted to slightly cooler summers, and will be one of the first of the slicer-sized tomatoes to ripen, and one of the last to produce at the end of summer.