United 휴스턴-유럽 스탑오버,오픈죠 발권 문의

안녕하세요.

내년에 유럽 발권을 알아보고 있는데요.

UA로 갈때 스탑오버-오픈죠-(아니면 오픈죠 안하고 스탑오버 두번) 된다고 글을 본것 같아서 여러번 시도해 보았지만 안되더라구요.

1. 아래구간에서 암스텔담을 2-3일 늘릴 수 있는 방법이 있을까요?

2. 다른 항공의 경우...휴스턴-스위스-스웨덴-휴스턴 코스를 다른 항공으로 좀 더 적은 마일로 가능한지 궁금합니다.

3. UA로 더 좋은 코스가 가능할까요?(뒤에 칸쿤을 붙인다던가....)

휴스턴이 UA만 허브로 이용하다 보니 유럽갈때 다른 항공사 이용하기가 어렵네요.

조언 부탁드립니다.

Flight Details

Wed., Jul. 22, 2015 \| Houston, TX (IAH - Intercontinental) to Munich, Germany (MUC)
Depart: 4:15 p.m. Wed., Jul. 22, 2015 Houston, TX (IAH - Intercontinental)	Arrive: 9:50 a.m. +1 Day Thu., Jul. 23, 2015 Munich, Germany (MUC)	Travel Time: 10 hr 35 mn	Flight: UA104 Aircraft: Boeing 767-400ER Fare Class: United Economy (XN) Meal: Dinner No Special Meal Offered.

Fri., Jul. 31, 2015 \| Munich, Germany (MUC) to Stockholm, Sweden (ARN - Arlanda)
Depart: 7:15 p.m. Fri., Jul. 31, 2015 Munich, Germany (MUC)	Arrive: 9:25 p.m. Fri., Jul. 31, 2015 Stockholm, Sweden (ARN - Arlanda)	Travel Time: 2 hr 10 mn	Flight: LH2420 Operated by Lufthansa. Aircraft: Airbus A320 Fare Class: Economy (X) Meal: Snack or Brunch No Special Meal Offered.

Thu., Aug. 13, 2015 \| Kiruna SE (KRN) to Houston, TX (IAH - Intercontinental)
Depart: 10:30 a.m. Thu., Aug. 13, 2015 Kiruna SE (KRN)	Arrive: 12:05 p.m. Thu., Aug. 13, 2015 Stockholm, Sweden (ARN - Arlanda)	Flight Time: 1 hr 35 mn	Flight: SK1041 Operated by SAS Scandinavian Airlines System. Aircraft: Boeing 737-700 Fare Class: Economy (X) Meal: Food and Beverages for Purchase No Special Meal Offered.
Change Planes. Connect time in Stockholm, Sweden (ARN - Arlanda) is 4 hours.
Depart: 4:05 p.m. Thu., Aug. 13, 2015 Stockholm, Sweden (ARN - Arlanda)	Arrive: 6:10 p.m. Thu., Aug. 13, 2015 Amsterdam, Netherlands (AMS)	Flight Time: 2 hr 5 mn	Flight: SK1555 Operated by SAS Scandinavian Airlines System. Aircraft: Boeing 737-700 Fare Class: Economy (X) Meal: Food and Beverages for Purchase No Special Meal Offered.
Change Planes. Connect time in Amsterdam, Netherlands (AMS) is 16 hours.
Depart: 10:10 a.m. Fri., Aug. 14, 2015 Amsterdam, Netherlands (AMS)	Arrive: 1:45 p.m. Fri., Aug. 14, 2015 Houston, TX (IAH - Intercontinental)	Flight Time: 10 hr 35 mn Travel Time: 34 hr 15 mn	Flight: UA59 Aircraft: Boeing 777-200 Fare Class: United Economy (XN) Meal: Lunch No Special Meal Offered.
! You are arriving in Amsterdam, Netherlands (AMS) on Thu., Aug. 13, 2015 and your connecting flight departs from Amsterdam, Netherlands (AMS) on Fri., Aug. 14, 2015. Note: You are arriving Stockholm, Sweden (ARN - Arlanda) and departing Kiruna SE (KRN).