Build for Michael on the Kickstarter comments -
As you suggested, this is a build starting with a Grand Citadel pledge, with a $3k budget and everything painted. It takes an eye towards integration with City Builder, and buildings on crags/integrated with cliffs in the vein of Ptolus.
This gives you a fully finished, 2 large tower fortress a bit bigger than a Grand Citadel with full Battlements, or potentially over 5 feet of City Wall topped with Battlements, or a 8 story Watchtower/Wizard Tower on top of a nice sized bit of mountain terrain.
Base Castle Parts
$980.00 Grand Citadel
$148.00 GC Inside Walls
$46.00 Cube Spacers (I might go with two sets here)
$78.00 Straight Walls
$46.00 Tower Breakout
$32.00 Large Tower Roof
$89.00 Motorized Drawbridge
$295.00 Battlements Megapack (if you prefer Crenellations, those are $150)
CBS Integration Bits
$58.00 Roof Platforms
$166.00 Stone Advanced Builderx2
$33.00 Square Tower Bridge Base
$35.00 Large Tower Bridge Base
$42.00 Tower Bridgex2
$48.00 Stone Bridgex2
$59.00 Large Batter Base
$48.00 Cathedral Roof
Mountains & Cliffs
$385.00 Erinthor Mountains
$65.00 Mountain Cliffs
$80.00 Mountain Elevation
Décor & Misc
$29.00 LED Floor Pack
$28.00 LED Lantern Posts
$25.00 Ruined Wall
$30.00 Ruined Tower
That leaves $130 to play with for whatever flavor pieces strike your fancy - the Siege Engines, Necromancer or Runic decor packs, more LED stuff, a Kobold horde, etc.
The main items you're going to use to integrate into your CBS builds are the Extreme Offset Walls in those Advanced Builder packs (also in the Battlements Mega and Drawbridge upgrade) which allow you to line up doors properly when transitioning from City Builder to Castle Walls. The various tower bridge bases are good for this too, transitioning from City Builder to Large Towers. You could use this for pedestrian access between levels in a cliffside city.
If you're building parts of a city like Ptolus, you really might consider working in 2 Erinthor Mountains packs somehow. Dropping the extra Cliff and Elevation packs and adding a second Erinthor would put you about $100 over budget here.
A trick to build up elevations which has been mentioned but isn't always illustrated super clearly, is that all the 8x8 floors (Flagstone and Mountain) have sockets underneath to accept City Builder posts upside down, and you can insert walls between all the posts to finish off the facade. You can see a bit of this in the Erinthor video linked below.
For perspective, this photo from the Kickstarter page uses a bit less than 1 Erinthor set.
This video Nate did is almost exactly one Erinthor.
https://ksr-video.imgix.net/assets/005/ ... 4_high.mp4
Edit: corrected typo, Stefan's cliff city (on the red tablecloth) was said to be around 1 Erinthor, not 2.