Good Budget Tour of Chitwan / Nepal?

Anyone know of a good, but cheap way of seeing the Chitwan national park. We are going to Nepal in late October (only11 days) and would like to do four stops. Jitpur (where I will volunteer later this year), Kathmandu, Chitwan National Park and Phokara. We hope to travel independently and take the days as them come, and so Chitwan is the one place we need to be a bit more organized seeing. We would like to do the usuals, elephant safari, jungle walks, rhinos, crocodiles etc. Can anyone advice me how to get the best from our visit, spending the least?? Is it best to get there on your own and find a lodge and a guide, or is it cheaper to book a tour from Kathmandu? We will be traveling from Kathmandu to Chitwan to Phokara and back to Kathmandu (losely planned anyway). Thanks guys!!
Thanks for your tip Badri

Chitwan National park is nice place to visit during October. My suggestion is to book a lodge or resort at Chitwan from Kathmandu itself. You may get discount package of Pokhara and Chitwan tour including safari, jungle walk, tourist guides etc. If you really want a very cheap lodges then you can get at the spot itself but you have to bargain. The price at the situation depends upon the number of tourists visiting at that time. Price fluctuates based on the number of visitors. But if you book from Kathmandu, you don’t have to worry.

Anyway, from my last experience, but long ago, 5 years ago, room may cost around NRs 500. Food cost (Nepali rice, vegetables, lentils) NRs 150. The elephant ride may cost you US$ 10-20 (including entry fee). The price may have changed by now I am not sure.