I understand the issues of time commitments and/or lack of "grappling/BJJ friendly" space for off hours training; those are pretty common issues IME.
Even though it's not an equal substitution, you could consider "shadow" grappling (just as boxers do "shadow boxing") as a way to at least get in some more reps of your skills and practice "chaining" them together. I would generally suggest premapping out some skills you want to chain together working through either common "bad" situations you encounter or offensive skills leading to a submission. Eventually you can let your imagination go and actually "flow" but that's a more advanced variation.
To give you a few examples of what this might look like off the top of my head:
1) Forward rolling breakfall (simulating getting thrown)
2) Coffee Grinder/Hitchhiker escape from armbar attempt (unsuccessful pass, opponent Granby rolls/inverts and regains their closed guard)
3) Knee on butt closed guard break into Knee slice pass to side control
4) Reverse sit out transition to Mount
5) Opponent "Upa" Escapes and you wind up in closed Guard
6) Flower/Pendulum Sweep to mount
1) Ouchi Gari attempt (unsuccessful, opponent steps out of it)
2) Transition to Osoto Gari (successful)
3) Knee Fold Armbar attempt (unsuccessful, opponent defends with coffee grinder/hitchhiker escape)
4) You transition to Omoplata before opponent can full pass your guard (opponent attempts to roll out)
5) You follow and transition to mount (biceps slicer is also there if those are allowed)
6) Opponent attempts to Knee and Elbow escape and you counter by transitioning to Technical/Side Mount, grab the collar and execute a Bow and Arrow Choke to finish
Again, these are just random chains of techniques that I put together off the top of my head that create the feel of a "flow roll" and can help you to recognize and possibly catch someone in something with a greater success rate. If these were two long for you, then you could always shorten it to 3, 4, or however many techniques you feel like you are capable/know of. They can also by any string of techniques starting from any position or situation that you know of.
At first you will probably feel a little silly/self conscious rolling around by yourself just as people usually do while shadow boxing. Eventually though that self consciousness goes away though and you will be better able to "let go" and be in the moment doing your shadow grappling.
Good luck, hope this helps.