What should I choose between Veterinary Corp, Warrant Officer Pilot, or Medical Corp? Which is best for Army NG or Reserves?

Which one will satisfy you the most? And how far do you have to travel for drill?

Hard to respond to this question without more details; where are you in the process of recruitment? What are your existing qualifications (do you have any degrees/training relevant to any of these fields)? What interests you in each of these? What do you hope to get out of your experience in the Army? These potential options are quite divergent to say the least.

Ralea Casperson that really depends on you and what you want in life. Two of these paths are pretty set in stone and once you are on it, you are on it. Hope you were understanding the Medical Corps as being doctors and other medical professionals vice a Medical Service Corps (MSC) Officer which coordinates, plans, organizes etc combat health support in a unit. Those are the tactical peeps in Army health care.
- Do you want to earn a DVM and treat animals?
- Do you want to earn and MD or medical specialty and treat patients?
- Do you want to fly rotary and fixed wing aircraft?
Its that simple...
- MD: high barriers to entry, hard work on your part simply to gain entry to medical school. Pass med school and residency (some pay), earn license become doctor (finally paid). Then there is specialization. Resource heavy. Reward in the middle.
- DVM: high barriers to entry, hard work to simply get into vet school. Pass vet school. Intern with a more experienced Vet, earn license become vet (getting paid). Specializations are essential in this field, like Equestrian Vets. Resource heavy. Reward in the middle.
- Flight Warrant: compete to be selected for WOCS, go to Basic Training, Pass Basic Training, attend/pass WOCS, go to flight school and pass, Specialize in an airframe. Get to your unit and work toward being a Pilot in Command (PC) and Instructor Pilot (IP) Resources less on your part. Heavy commitment. Getting paid while doing it. Better like flying because that is your primary function in life. Reward is more front loaded.

This may not be of great help but here is a way to come at it.
https://www.rallypoint.com/command-post/how-do-i-choose-an-army-branch-a-framework

Ironically all three have great after the military careers or simultaneous careers for the Reserve Components (ARNG and Army Reserve). All three are almost completely mutually exclusive (MEDEVAC pilots evac patients from point of injury to proper echelon of care, stretch of a touch point). You are going to have to make your choice. Once you get on one of these paths that is it unless you have unlimited resources. Military doors will start to close depending on your age and the option you consider.

I have operated under the assumption you are not trying to enlist in these fields. There are enlisted military occupational specialties (MOS) in each of these branches. that is a whole other conversation. All three of the things you had in your post are officer positions. All commissioned officers except for the very beginning of a Warrant's career as a WO1, CW2 on they are commissioned.

PS Corp = Corporation, which we are not. Corps = Military organization that represents either a branch or a operational headquarters commanded by a three star.