By far the best advise here is the above. A few additions.
It is none of our business and you don't need to fill in details, but use your own knowledge about what you have been trained to do and what that job market is like and likely going to be like. Many new graduates MUST find work in their chosen profession very soon after graduating or their degree becomes 'stale' and later graduates will be given preference over them. If that job is your dream job and the above applies you do everything you can to get that job and you do not mention the trail. This is just being smart and mature. Another issue for you is that it 'seems' as if you have used your relationship with your professor to help you get in line for this job. If you do something stupid and it all goes sour that professor is quite possibly going to not be pleased that they used up 'their' equities on someone who turned out not to be what they thought they were and will be unlikely to ever recommend you again. Professional relationships are/can be very important to build in many professions (does this apply to you? - if so...). Do you have large student loans which will be in need of servicing? I should not need to state in today's world and economy that there is LOTS of competition for any 'dream' job. There is no guarantee it will come around again. The job, as you mention, is what you hope to make your life of - just fyi the Trail IS NOT YOUR LIFE and you do not want it to become your life. The Trail is a really nice 'vacation' which can easily be replicated in other ways like section hiking should you have to wait until you are retired to thru hike like I did and many like me.