add note about trailers, link ticket page from travel, small restructuring

docs/tickets.md

@@ -26,7 +26,7 @@ For more Details read the [blogpost](https://events.ccc.de/2023/05/29/camp23-pre
 
 ### Add-Ons
 
-You will need an extra ticket to park your car, as well as you will need an extra ticket to bring a camper van.
+You will need an extra ticket to park your car, as well as you will need an extra ticket to bring a camper van. Parking for trailers will be free as long as they come with a car with a parking ticket. 
 
 | Type | Price (€) | Remark |
 | --- | --- | --- |

docs/travel.md

@@ -73,6 +73,7 @@ Details are still being worked out.
 Please do not travel via car if you have other options available to you.
 Not just because of your carbon footprint but because handling 2000+ cars and the space they consume is no small task.
 We'd prefere to use the space for villages and cool blinking stuff instead of parking space.
+You will need a [parking ticket](tickets.md) to park your car. Those are sold during the presale and on site for cash.
 
 But for some, travel by car is the only viable option, in that case:
 
@@ -87,8 +88,6 @@ Please do **not** arrive with an empty tank of gas and rely on a gas station clo
 Those will be overwellmed and run out of gas, leaving you stranded. This was tested 2019 and we would prefere to spare you from it.
 Please fill up your tank **before** you get close to the location, at best while still on the highway.
 
-You will need a parking ticket to park your car. Those are sold during the presale and on site for cash.
-
 ### Unloading
 
 * Driving a car onto the camp site is only possible outside of the official event period.