Wouldn't you highlight the section and use the Find/Change command under Process?
When you open track in Event List View you can see the current durations to figure out what you want, but that is a very tedious way to change them.
If you want them all the same length (like 30 ticks), do Find/Change to select All and then Change duration to 0 30.
If you want a range of lengths, you can still use Find/Change. If the shortest length currently is 100 ticks and the longest is 200, for example, you can put 100 and 200 in the Find box under duration and then put, again for example, 50 and 100 in the change box.
You can also use Edit | Select by Filter to select only notes that are within a certain duration range so that the Find/Change command will only affect them. That can really be accomplished in the Find/Change facility itself, but sometimes it is safer and less confusing to select only the target notes.
Personally, I would look at the music in Staff View and highlight the section I wanted because I think in terms of notation—but that may not apply to most people.
Related Topic: Everyone is different, but because of my style and habits (and my OCD personality about organizing my music), I am always very aware of how many ticks represent each musical duration. Example: if you use a 120 tick per beat clock in Preferences, quarter notes are 120, 8ths are 60, sixteenths are 30, whole notes in 4/4 are 480, etc. I always check the Duration box in Quantize to make sure I get the durations I want during quanitization so I don't have sloppy note lengths. (I have heard people on this forum say that it is more human to have uneven durations, and they are not wrong; however, I have worked with many conductors and producers who will make musicians play parts over and over until the durations and cut-offs are right on the money.
whatever works for you.)