On the whole Israel is a fairly good country to visit for people with disabilities with respect to tourism. It can be more difficult in the cities.
http://www.parks.org.il/ParksENG/ganim_about.php3
This is the english site for the Israel Nature and National Parks Protection Authority if you want to travel on your own some days. Some of the parks are specifically marked as wheelchair accessible. It also give opening times and telphone numbers. You can always telephone to check with them even if it isn't written there. Websites are not always updated.
Have a good time
I have become my own version of an optimist. If I can’t make it through one door, I’ll go through another door or I’ll make a door.’
Rabindranath Tagore