There is a link to their route map in related links below.
The closest airport is San Jose.
Southwest does not fly to Miami. The closest airport that Southwest serves is Ft Lauderdale.
Gulfport, MS Biloxi/Gulfport International Airport
Tampa International Airport
No, currently the airlines that are flying out of Manchester-Boston Regional Airport is Delta, Southwest, United, and US Airways. The closest airport to Boston, Massachusetts that American Airlines flies from is BOS- Boston Logan International.
Brownsville/South Padre Island airport is the closest airport to South Padre Island. It is serviced by Continental Airlines. Harlingen is just a little farther & is serviced by Continental & Southwest Airlines.
For private planes the closest airport is Whiteman (WHP) about 15 minutes to the west. For commercial flights the closest airport is Burbank (BUR), about a 20 minute drive to the southwest.
The closest airport is RDU, but the scenery between CLT and Greensboro is prettier so I think it's worth the extra half-hour it'll take to get there.
You could use either SMF (Sacramento) or SJC - (San Jose). Of these two, Sacramento is the closest and easiest to use.
The closest major airport to Americus, Georgia is Southwest Georgia Regional Airport (ABY / KABY). This airport is in Albany, Georgia and is about 37 miles from the center of Americus, GA. If you're looking for domestic flights to ABY, check the airlines that fly to ABY.
The nearest major airport is Tyler Pounds Regional Airport (TYR / KTYR). This airport has domestic flights and is about 6 miles from the center of Tyler, TX.
Pensacola
The closest major airport to Carmel, California is Monterey Peninsula Airport (MRY / KMRY).