Messias, training solo really is a large part of effective training, even after people have been on the mat for years. In fact, after awhile, the training can become part of everyday life - even in the way we sit, stand, walk, move, open doors, put the dishes away. There's always places to study and play around. It actually becomes a sort of mindfulness - an attention, an opening in consciousness that can help keep us more awake.
I think if more people would train solo before they ever even stepped on the mat, they'd be more prepared to really learn. A lot of people who come into aikido have to actually be deprogrammed, and rewired. The main thing we run into, especially in the West, is the idea that large muscle groups and their use are our source of strength. We can move into an entirely different level of strength by disengaging the large muscle groups and tapping into the intrinsic strength in the body's natural design.
I'm actually working on developing something especially for people like you, who are remote and may not have access at times to training places. And even for people who do train, as something supplemental on aspects that might not be so readily apparent.
Have a look at this video, in which I explain that your skin is what makes the structure of your body.