The artist’s instructions for integrating the buildings into the platform are very good. The Balsa wood trick is easy and works well. The only thing I'd add to the Balsa Wood process is to glue or double side tape the Balsa strip to one of the pieces because you'll get a much better fit. And, there are two other tricks that I discovered that will save you a lot of time and will make the Platform look great.
Easy way to fill the gap behind the buildings:
Buy a 1 qt bag of Woodland Scenics Clump Foliage in Dark Green (FC684). I promise it will be the best $5 you've ever spent. Place clumps of the Foliage in the gaps behind the buildings. It looks just like a nice, lush, green, hedge! It's very easy - much easier than trying to cut balsa. And, the springy nature of the foliage also presses the buildings forward toward the street holding them firmly in place.
Here's another example of how the foliage looks behind the buildings compared with plain balsa. The photos aren't quite identical, but you can see how the foliage adds height, texture, and color to the wall behind the Plaza Inn. It also helps disquise the break in the wall.
Some collectors have complained about the blank white wall behind the Astro Orbitor. Using the foliage behind the Astro Orbitor dramatically softens the wall, adds interest and height, and breaks up that flat expanse of white. The green foliage also helps integrate the Astro Orbitor into the general look of the Platform.
In the example to the right we're using the Light Green foliage clusters to soften the gap between the Castle and it's adjacent pieces, Triton's Grotto and Carnation. Without the foliage the gap is quite evident and distracting. With the foliage in place the gaps are much less evident and the overall look is much clearner. And, it takes only a few seconds to do.
Here we're using the foliage to fill in the area between the trees on the East side of Main Street. It completely hides the wall and makes for a more lush look. In fact, I used the foliage almost anywhere there was a gap. I think it's one of the great "no brainers" in the construction of the platform. Let me know what you think.
Using Caulks to Fill Gaps:
Travis strongly recommends installing the buildings such that they can be removed easily and allow the replacement of those pesky 1.3mm light bulbs. Besides, the Balsa wood technique works fine for most of the straight gaps between the buildings and the street. While generally true, there are two places where I found that using a Caulk was easier than using balsa. When I refer to "Caulk", I'm talking about using paintable, water soluable, adhesive Caulk like this one.
The first place where I used Caulk was around the Train Station. It's already glued down and can't be moved, so adding Caulk was not an issue. With a little masking the caulk went on easy and made a much flatter and cleaner installation than is possible with Balsa especially on the Street side of the Station.
You can see the finished result on the Street side of the Train Station. This is an area that's very difficult to look flat and clean with all the different levels of the pieces coming together. With the Caulks you can make the transitions look very smooth considering the differences in height of the pieces involved.
The second place I used Caulking is the area around the Hub and Town Square. The gaps in those areas are inconsistent and have dramatic curves. I couldn't figure out how to get a clean look so I came up with a way to use Caulk and the result was great. Here's what you do using the Hub as an example:
Pull the Hub out of the platform. Cover the hole in the platform with Painters Tape. Cut out the hole with an exacto knife. Cover the Hub with Saran Wrap and tape it down so it won't move. The Caulk won't stick very strongly to the Saran Wrap. Place the wrapped Hub back into the hole at the desired height. Pump Caulk into the gap so it extends down 1/8" or so. Use a piece of wood or blade to flatten out the Caulk making sure that very little is on the Saran Wrap above street level (it's hard to remove later) and so that the tape is showing. That's when I took the above photo. As soon as you're done with the smoothing remove the painters tape. Wait 24hrs. Loosen the Saran Wrap from the Hub. Pull out the Hub leaving the Saran Wrap in place. Carefully pull back the Saran Wrap off of the Caulk. If the Caulk is still squishy wait another 12-24hrs. Once the wrap is off wait another 48hrs for the Caulk to completely cure (else the Hub will stick to it). Then all you do is paint the Caulk, put the Hub back into place, and you're done. There's a lot of waiting for the Caulk to dry, but it's only an hour or so of actual work.