Hey Brandon
I recently had a grease pad that was in similar condition to the one you are looking at.
I think for pricing you need to ask yourself how much you want to make as well as if you are getting other work from the customer - maintenance agreement, sidewalks, canopies, storefront, etc, etc. For me the chance of getting this kind of work would help dictate my pricing... not to do it for a loss or to 'just break even', but if you do the job well - subsequent cleans are bread and butter!
Learning from my own experience with the grease pad I did, I would recommend putting down an absorbent of some kind (sand and kitty litter) and crush it into any 'fresh' grease - then sweep or shovel it up... after you have removed all debris and litter, etc.
... I didn't put an absorbent down and I think not doing it made my job harder.
If it were me, I wouldn't X-Jet or downstream the caustic - I use a shurflo pump to spray my mix straight on - then like DJ said, dwell, HOT water, repeat.
Remember to keep asphalt wet before, during and after and spray down all surrounding surfaces before during and after to make sure that caustic doesn't damage them - also washes any overspray.
... If you can arrange to have the dumpsters moved, do it - if it's not practical, work around them.
Hope this helps a bit.