Since you observe, I would suggest the Kibbutz Lavi Guest house. Lavi is a religous Kibbutz, and I heard that their guest house is very nice. The prices look fair to me. Check it out at:

http://www.kibbutzlavi.co.il/hotel/indexE.asp

Kibbutz Lavi is very popular for Passover so you have to book soon. Other options might be found at www.zimmeril.com/english. Don't use the contact form available at the site. My experience is that it does not work. Call or email directly.

Kinnar is another religious kibbutz (glatt kosher) you might wish to try - have a look at kinar.co.il . Another suggestion could be to contact a travel agency which specialises in religious groups and can therefore get you a special price at a religious hotel or guest house - try for example http://www.tourplus.co.il/en/index.cfm

Enjoy!!