The starscape mat looks interesting!
The corners, crossings and T-crossings weigh about 250-275 grams each, the corridors weigh approximately 100 grams per square of length - 500 grams for the long corridors, for example. The rooms vary between 750 and 850 grams.
All weights are approximate.
The corridors, including the corners - 8 kg
The crossings and T-crossings - 3.5 kg
The six rooms - 4.9 kg
Total: 16.3 kg (or actually somewhere between 15 and 17 kg)
The full set can be accomodated in 6 Muji boxes (with 2 drawers in each), and 2 of these boxes will squeeze-fit into one of the large plastic Ikea bags. Each fully loaded Ikea bag will weigh about 5 or 6 kg.
Hmmm... I wonder if it would be possible to build a game board inspired by the first Stockholm Ikea store... :-)