I know there are numerous mods like DarN, MTUI, etc., to make font sizes smaller and menu text windows larger, and those help somewhat. But I'm finding as I try a KB/M playthrough of New Vegas that the menus are just drastically more frustrating and tedious to navigate using a KB+M than they are with a controller. Some examples of what I mean:

-Need to mouse over a viewport in order to interact with it via keys, then mouse away again. If you don't mouse away again, scrolling will often become "stuck" and refuse move. If an item is selected and moved (e.g., trading an item to a merchant), the viewport has to be reselected yet again. This makes trading large numbers of items incredibly difficult.

-PageUp/PageDown work in some screens, but not in others.

-Escape doesn't exit dialog.

-No "Take All" command on companions.

-Inconsistent hotkeys for exiting and interacting with various menus (sometimes leaving a menu is E...sometimes it's X. why can't it just be Escape? Nobody needs to mess with settings in the middle of a menu). Sometimes there is no hotkey at all that I can find (is there one for leaving terminals?)

-No easy way to just type in the number of items you want to transfer -- you have to use arrow keys or the mouse.

-Probably a bunch of other stuff I'm just not remembering right now, but you get the idea.

The net effect is that menu interaction is a total clickfest and vastly worse via KB/M than it is with the controller. The shooter type stuff, though, obviously wants a KB/M, so I'm at a bit of an impasse. Ideally what I'd like is a UI mod that allows menus to be navigated entirely using they keyboard in a sensible way. Does such a thing exist, or is there anyone out there who's still modding for NV who be inclined to do such a thing?

You have to tell the NPC good bye to exit conversations, so there is no Keyboard way to do that.

As for your mouse issues, try updating the mouse software (or disabling it) as I don't have a scroll lock issue like you describe. Also, look at trying a wired mouse if you have not yet. That helped a lot of my mouse weirdness in games.

As for Activation with the Keyboard, I remapped the Space bar for that and it gets me in and out most menu interactions, other than the ones that I have to choose a selection in the conversation or the value.