Mastery, you want a qualified instructor. But, that's not to say there isn't anything you can learn on your own. Let's consider these factors:
You can do a lot of conditioning exercises on your own. A lot of the strength, balance and flexibility training can be done solo, and in many cases are not very different than calisthetics outside of kung-fu. Honestly, a lot of traditional kung fu training has you doing a lot of this for the first few years anyway, so you'll be on track here.
For anything involving weights, spinal twists, low stances, or holding stance for a long period of time, make sure whatever references you have are going in-depth into form. You don't want to find out you've ground away the cartilage in your knee from bad form.
Internal arts that work on coordinating core muscles or specific subtle muscle groups ("practice getting movement out of your intercostal muscles...") are things that are not well suited to practicing without an instructor.
Forms and Drills
You can learn a lot of forms and drills with striking bags and training partners. This you have to be a bit careful with and make sure the instruction materials are clear and precise about what you're supposed to be doing here to generate power.
There's a lot of folks who learn these and can't throw a strike, or have no idea how a movement is supposed to work.
Again, some forms are simple and straightforward on this, and very subtle ones will not be good for self-study. The subtle movements don't show up well on video and many schools of traditional Kung Fu simply do not tell you what they're doing that actually generates the real power unless you're an advanced student.
Classes cost money! And they may not be near you.
Seriously consider if you can go to a workshop or seminar to get some basic skills. You can let the instructor know your situation and have them focus on giving you a few things that you can drill on your own very well, and next time you can train with them, they can correct things. You may find other students in the same situation as you, and you can form training groups between the times you get instruction.
There's a place you reach in proficiency where you don't need an instructor for most of the training you have - you'll know what it's supposed to feel like, and have goals for what your movement should be like. Obviously, having a teacher is better, but you can at least maintain and excel in some areas on your own, between the time you can get training. That said, you get here only after you've gotten some good training and core aspects in you.