If you have a number of Cakewalk projects, each one representing a song on an album, what would you consider is the most useful way to consolidate them for mastering as a single album?
 
More detail: All my projects contain bussed stereo sub-mixes, labelled things like 'Guitars', 'Bass', 'Drums' etc. These sub-mixes finally go to a 'Master' stereo bus. (I learned how to do this ages ago from the 'basic' template that came with X3). I'm deliberately doing virtually no 'per project' mastering on this bus, though the sub-mixes and tracks are compressed and EQd etc...
 
My original plan was to export all the 'Master' buses and import them as separate tracks into a new 'album length' project, in order to master the whole thing as a single entity, but now I'm starting to consider exporting each of the sub-mix buses, so I have a new project containing an album-length 'Drums' track, an album-length 'Guitars' track etc etc..
 
I've only ever mastered a single song at a time, and I tend to just do it in-project on the Master output bus, hence the question
 
How would you do it? How do the pros do it? Any tips to keep things sounding consistent across a whole album?

I wouldn't try to mix and master CD-length stems.  I can't imagine what for.  Export each song as a master.
 
Mastering is supposed to help tone-stamp separate mixes so they sound more congruent.
 
 

I wouldn't attempt to mix such a long stem, no. I'd be doing overall mastering on anything that was CD-length.
 
How is it done by the pros? I can find plenty of articles about mastering but nothing that really talks about consolidating projects and achieving consistency over a longer period of time like an hour.
 
EDIT: Actually, this is a good read for some opinions: https://www.gearslutz.com...ether-whole-album.html

Stems are used to give the mastering engineer more flexibility, essentially providing him with a way to modify your mix on a macro level. MEs love this, because they are so often expected to fix things that should have been fixed in the mix.
 
But since you are both the mixing and mastering engineer you don't need that capability. Go with your original plan, keep it simple and export 32-bit stereo wave files for the mastering project. You can still apply separate plugins to each song if necessary - just load the imported pre-masters into separate tracks in the mastering project.
 
I like to use a separate audio track for each song, which lets my apply EQ and compression as needed. First step is to identify the hottest track and use it as the reference for all the others, turning them up to approximately match its volume. Do this by ear rather than meters and don't worry if turning them up results in scary peak values. If one track is too peaky to turn up to match the reference, apply some compression or (gentle) limiting.
 
Don't overlook the biggest advantage to using a separate mastering project, which is adjusting the gaps between songs. Listen to how each flows into the next - you might even alter the song sequence if a transition is too jarring. At the end of one song, keep counting the beat in your head while waiting for the subsequent song to begin; if it's a similar tempo then you'll want it to start on that imaginary downbeat. Also consider crossfades instead of silence, which can be very effective when the songs are in the same key, or when the first song ends with a fadeout.
 

Thanks bitflipper that's great advice.
 
Regarding track transitions.. I also approached that with a plan :) I'm covering a concept album that has a number of tracks that run directly into one another. To make this easier I've 'grouped' the main culprits into the same projects. So project 1 is song 1 and 2, project 2 is songs 3, 4 and 5, project 3 is songs 6 and 7 etc... This was also intended to make keeping a consistent sound slightly easier.
 
The transitions that I edit in my mastering project will be those transitions that are the most "end of this, start of that" black and white scenarios.

When putting songs together for an album I start at the track level.
I try and use the same "Band" as in the drum kit, bass, and keyboards can be kept the same if possible. You can change kit pieces but I will leave the Kick the same for all songs. Having your low end consistant makes life easier for the final mix. 
Then I use sub busses and try and use the same levels, compression, EQ for each song. Track templates are your friend here. 
If the vocals are all by the same person I also treat that the same on each song. 
 
Following this simple plan makes it very easy to mix all songs to sound very close.  
 
Then I export each song and do all my mastering in a wave editor. ( Wave Lab) From there they can be batch converted to what ever format needed. 
Then I listen to these on a bunch of different systems. 
For CD I use Nero to burn. 
If there is a final album order I might stick the track numbers in front of the file names so it will play in order on a USB stick in the car. 
Once I'm happy I release the album to client or whatever. 

I export each song at 32 bit resolution.
 
Each song is then imported into my mastering template with each track exactly where it needs to be on the timeline
 
My template also includes a few Vsti's which get triggered to segue properly into the next song
 
Some even include a small chunk of audio with key signature changes to make it sound more natural
 
If you've mixed according to K14 rules then it's possible to do all this and have all your track faders in the mastering project at 0dB and not get any abrupt volume changes between one song and the next

I open every song/project in Sonar and size the windows so I can cascade them from top left to bottom right.
 
I then listen to short bits of each in turn, switching rapidly between songs so's to keep the sound of each song in my head.
 
I adjust each song so they all end up sounding like they belong together.
 
What I am looking out for is similar bass weighting, similar loudness (as in compression as well as volume), brightness, main instruments panned the same, vox/backing balance, etc.
 
Otherwise it ends up soundling like a mixtape of different albums. It must feel unified.
 
But to be honest I have next to no call for mastering to CD or any form of sequential "album" format anymore. Bands want mp3 files straight to their phones. No interest in the WAV files either.