Richard:
 
I suggest you get in on the evening of Wednesday, Nov. 7 and depart in the afternoon (probably 3pm or after) on Nov. 9.  
 
As for travel, I guess it depends on your budget and schedule - those flights with stops aren't necessarily very convenient.  You should call the Travel Agency in the Park, but my quick search on-line found that the only direct flights, on Continental, are running just over $1,000.  America West tickets with a stop in Phoenix are about $450.  I found a flight on Southwest departing from Hobby (via Phoenix) for $385 (see below).  
 
 
Air Itinerary	
 Trip 	  Date 	  Day 	  Stops 	  Flight  	 Routing	
  Depart  	 Nov 7	 Wed	 1	 1364	 Depart Houston Hobby (HOU) at 4:35 PM and arrive in Phoenix (PHX) at 6:20 PM	
2048	 Change planes in Phoenix (PHX) departing at 7:20 PM and arrive in Portland (PDX) at 9:10 PM	
  Return  	 Nov 9	 Fri	 1	 642	 Depart Portland (PDX) at 3:25 PM and arrive in Phoenix (PHX) at 6:55 PM	
1383	 Change planes in Phoenix (PHX) departing at 7:45 PM and arrive in Houston Hobby (HOU) at 11:05 PM	
  	
On Frontier, via Denver, I found the following for $252:
 
Your Itinerary	
Departing Flight	  	
 	 Wednesday, November 07, 2001   	  	
323	 Depart Houston, TX (IAH)	 2:45 PM	  	
 	 Arrive Denver, CO (DEN)	 4:10 PM	  	
connecting 797	 Depart Denver, CO (DEN)	 8:40 PM	  	
 	 Arrive Portland, OR (PDX)	 10:15 PM	  	
Total Travel Time	 9 hrs. 30 mins. 	 	
  <https://ww5.vibef9.com/booknow/images/icons/pixel.gif>	
Returning Flight	  	
 	 Friday, November 09, 2001   	  	
794	 Depart Portland, OR (PDX)	 3:25 PM	  	
 	 Arrive Denver, CO (DEN)	 6:50 PM	  	
connecting 328	 Depart Denver, CO (DEN)	 7:35 PM	  	
 	 Arrive Houston, TX (IAH)	 10:45 PM	  	
Total Travel Time	 5 hrs. 20 mins. 	 	
  <https://ww5.vibef9.com/booknow/images/icons/pixel.gif>	
1 Adult	 $212.09	
Subtotal	 $212.09	
Taxes and Charges	 $40.41	
Total (USD)	 $252.50