e-savers from PHX: TPA is $129 each way before taxes, and Florida is pretty cheap; rent a car, drive 3 hours, and fly back from MLB - 3 points.
Try San Juan, PR (SJU) for Caribbean for 3 points at $355 and no immigration or customs hassles, but can route in via PHL and out via CLT in one day - (and add in LAS-PVR trip for 4th point.)
-- Note also that lower fares at your connection points may price an itinerary cheaper at the US Airways site, such as cheap CLT or Philly e-savers enroute, or cheap Chicago fares.

Also - Try your routes from Las Vegas.
e-Savers has LAS-PVR at $109 each way + tax [vs. $150 from PHX]. Try PVR Intercontinental $88 rate, and there is a 2-for-1 rate in HI forum, or use Expedia rate with free tropical tour added, if you stay (and not turn around). 2 points but cheap.
Otherwise LAS-BOS, with shuttle, and work in BOS-PBG (probably overnight) for 4 points.

There are some excellent fares from PHX and LAS found on the farecompare.com/search/flyertalk.html page with "LAS" and "PHX" as an origins to help you, filtering on US Airways as carrier filter (left side, "only" button). Default is sorting by Price per mile (PPM), but you can click on the word "Total" for that column to be the sort filter for the results, too. Note that it does not include e-savers, and it is the fare filings, so not all markets will price out at the lowest shown. Use weekly low-fare-finder search on USAir site to assist finding best dates to match these. Here with US destinations:
Lowest by Total:
Phoenix, AZ Fort Myers, TTL$237;
Phoenix, AZ Cleveland, TTL$240
Phoenix, AZ Nashville, TTL$240
Las Vegas, NV New Orleans, TTL$246
LAS-CLT $278
**LAS-BOS $279 (gets you the shuttle if you work your schedule right) and may add BOS-PBG for $52 each way if purchase in advance. This is probably your most compact option.
(Then the Florida fares, etc. below)

Lowest buy Price per mile (PPM):
PHX-FMY $237; PHX-BDL $280 **; PHX-PWM $300**; PHX-CLE $240; PHX-PBI $277; PHX-RIC $277; PHX-PHL $279; PHX-BWI $279
Las Vegas, NV West Palm Beach, $257
Las Vegas, NV - Fort Lauderdale, TTL$260
Las Vegas, NV - Wilkes-Barre (AVP), TTL$276 *
Las Vegas, NV - Newport News (PHF), TTL$277 *
**Las Vegas, NV - Boston, TTL$279 4764 miles$0.06 - try to work in shuttle and may add BOS-PBG for $52 each way if purchase in advance, as above
**Las Vegas, NV - Bangor (BGR), TTL$316 4962 miles$0.06 try to route via shuttle
Las Vegas, NV -San Juan, TTL $355 6440 miles$0.06 - 3 points.
You get the picture...

Try using the "multi-city" flight search to do a circle trip - PHX-florida, and then up to BOS via Shuttle / PBG (new market; $52 each way; register for miles bonus, too, and back to PHX/LAS. - 4 points.
Or from PBI/MCO/TPA drive to MLB (o/w car rentals in Florida are cheap) and/ or fly up the east coast (via shuttle) for a new market MLB-CLT) and then back - 4 points
Or fly to SJU, and then to ROC, back via shuttle and back to PHX/LAS for 4 points.