I will describe the currently available navigation related features:
1. Alt + Left / Alt + Right - Moves backwards and forwards based on the navigation stack. This is useful to jump back and forth between the last recent subs.
2. Alt + N - Opens the navigation stack menu. You can then choose the location with the up and down keys.
3. If you are working on two locations in the same module then you can split the code editor (it can be split again vertically):
4. If you are working with multiple modules:
5. Ctrl + E - searches for sub or module. Very useful when working with large projects.
6. F7 - Find all references. Not exactly related to navigation but is also useful when working with large projects.
7. Ctrl + Click on any sub or variable to jump to the declaration location.
8. Ctrl + F - Index based quick search. If you really miss the bookmark feature then you can easily implement a similar solution (actually better) with comments such as:
'b_1
'b_2
Now you just need to press on Ctrl + F and enter b_ (if it is not already there).