First I would look into whether the .ca is actually necessary.
Each market is different and each site is different, but for my sites at least they tend to rank pretty well in the international versions even though they're .com and hosted in the US. Sometimes they rank better in the international versions than they do in the worldwide versions! I suspect this is mainly due to the fact that my sites tend to attract links naturally, so have attracted some links from sites that are in fact .ca (or .co.uk or .com.au, etc) geo located. And of course because my targeted search phrases are considerably less competitive in these regional engines since my competition apparently doesn't attract links the same way my sites do.
In other words, you might want to check to see if you actually have a problem to fix before you start trying to fix it.
The problem being this can be a little difficult to ascertain if you're not in those countries. To be absolutely certain you almost need to either find someone in those countries you want to target to do some search research for you. Or find yourself a proxy IP that maps to the country in question so that it looks to the search engines like you're arriving from that country.
Another way you can sort of tell is to dive into your web stats to see if you're getting a decent amount of traffic from those other countries. Though don't expect it'll equal US based traffic because it probably won't quite make it to that level.
Or, something I've discovered recently, if you're concerned mainly about Google and your site happens to be php I released a little tool a few days ago I've been tinkering with the last couple of months that pulls some information from Google's new referral url structure. The tool is still Alpha at this stage, but it'll pull the information. I just need to find some time to build a front end to help sort through the information to make it a bit more useful. Or hope someone else will find the time to add a a front end.

I'm hoping someone will port it to ASP and other languages as well since I know I'm not going to find the time to do that kind of thing. Though for something like what you're talking about (geo stuff) it would be a pretty simple MySQL statement to pull the info you need. I've done it several times with my test bed sites the tool is active on.
I've coined the tool
Google Rank Extractor. More info and the download is available on my personal blog if you want to give it a whirl. (Yes, it's a freebie that's release under a GPL license.)
Now on to your questions in case you've already sorted out that you have an issue that needs to be addressed.
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1) I consider my whole site's current content to be both of international interest and local interest. I don't have any pages that would be better candidates to make or not make into geo-specific pages.
This statement would lead me to believe that you don't really need to do the type of geo targeting you've asked about. If the site is genuinely worldwide why would you want to even attempt to start geo targeting? I mean you'd literally have to do it for
every country and region out there. Or at least all English speaking regions. That seems like a lot of work for very little potential benefit.
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1 cont) Can I set up all of the internal on the sight so that they are available through th ccTLD, or would there be any concerns with this such as dropping rank with .com version in world wide searches due to "overdoing geolocation internal linking" for instance?
I wouldn't recommend this. Your .com will end up suffering in the rankings because by your internal navigation you're basically telling the search engines that the entire site is ccTLD in nature. And you'd be orphaning your already indexed and ranked .com pages because there is no 301 redirect in place.
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2) I have different servers for the .com and ccTLD. The uploaded physical pages will have to be uploaded twice; one set to each server so that as you put it, the physical pages can be reached through both domain names. Will it be a problem to upload duplicate pages of the entire website to the .com server and then also to the ccTLD server? (eg. duplication concerns, or does the parking alleviate the duplication concerns?)
That's not really a problem, regardless of whether the ccTLD is parked on top of the .com or if it has its own local server. The search engines
will see it as duplicate content, but there is no duplicate content penalty so they'll simply display the version that's most appropriate for each individual user. In practice this usually means the Perfect World scenario would have the .ca pages would show up for Canadian searchers while the .com would show up for US and worldwide searchers.
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3) It may be that all I need to do is pick a select number of pages to become "the local" pages within the site and set up internal links for those pages only to be available through the ccTLD. My question, if I were to go this more limited and "non-greedy internal linking route", would the content on the pages of the .com version of the site that are not available via internal linking through the ccTLD, eventually get indexed for home country specific search results anyways?
As you've laid out the question this would certainly be a more measured approach. One that would allow you to do a little testing to see if it's really necessary to spend so much time and expend so much effort on the international rankings for your site. You may in fact find out that it's not worth it for a variety of reasons, possibly including that your .com pages are already ranking quite well in those international circles.
Again, given the scenario as you've laid it out I would suggest first trying to find out if it's really a problem you need to address. Because if it's not your time could be better spent on other efforts.