1) Yeah, don't assume your score. Leading upto my first LSAT I was consistently in the 170s for the last 2 months. My last 3 practices were 173,175,174. I got a 167 on the test.
2) IF you score in the 170s on the real test, you will probably get a full ride or two to some top 25 schools.
3)You can get loans assuming your credit isn't terrible.
4) If you're going into public interest, many schools have loan forgiveness programs. These programs differ from school to school, so it's worth researching.