USSF-106 is a mission for the United States Space Force. The launch will deploy various payloads directly into geosynchronous orbit, including the NTS-3 (Navigation Technology Satellite 3), a demonstration navigation satellite testing a new digital signal generator that can be reprogrammed on-orbit to broadcast new signals, improve performance by avoiding and defeating interference, and adding signatures for detecting spoofing attacks.
TLDR: Best viewing location depends on which launchpad you're there to see, scroll below for more details. I've listed only the currently active pads. This list covers both Kennedy Space Center and Cape Canaveral.
Kennedy Space Center has three official viewing locations, all bookable on their website.
Visitor Complex: The cheapest ticket, general admission will cost you $50. That gets you about 11.5 kilometers from all launchpads. It's ok but not great since direct line of sight to the launchpads is obscured by trees. Essentially you watch the jumbotron until ignition and then look up once the rocket clears the treeline.
LC-39 Observation Gantry: The closest official location to all the launchpads, from about 3.5 kilometers to LC-41 up to 9 kilometers to LC-37. Tickets will cost you $70 on top of the general admission price above. This building is closed to the public for launches on pad 39 since it's too near the launchpad.
Banana Creek at Apollo/Saturn V Center: Best view if you can't get tickets to the gantry. It's next to the Apollo/Saturn V Center and distances range from 6.5 kilometers to LC-39 up to 13 kilometers from LC-39. Access is via their $250 per person package. It's a hefty price tag but worth it for the good angle. This is the view seen in the video at the top of the guide.
Once in a blue moon they'll open up a VIP or personnel viewing area to the general public. I don't know what triggers this but when it happens the tickets go up on their website just like the other locations. This could be the East NASA Causeway or the holy grail, the ITL Causeway. If you see these take them, you'll get a better view there than anywhere else.
All options (except the causeways) have a jumbotron and live commentary. Tickets can in theory be purchased on the day but will be sold out well before launch. The gantry in particular will sell out within a few hours.
There are also good views from public locations near the launch site.
Playalinda Beach: For LC-39A since the gantry is closed this is closer than any official location at 5 kilometers. For LC-39B the beach will always be closed since it's too close. For all other pads it's the best public spot. Unfortunately it's often closed without warning on launch day at the agency's discretion. Normal hours are 6am to 8pm. Note that parking at the first lot will likely fill up but if you keep driving north there are additional lots. Just a word of warning at the northern-most section it becomes a nudist beach ("pier 13", near the 13th parking lot).
The view in the photo at the very top of this guide is Playalinda Beach.
Max Brewer Bridge: About 18 kilometers away from LC-39 and a bit more from the others. A slightly better view of the northern launchpads than the visitors complex. When Playalinda Beach is closed this is probably your best bet for a free and public viewing spot.
KARS Park: This is a NASA-owned park on Merritt Island that has recently (late 2023) begun allowing non-NASA visitors in on launch day for $5. This has good views of all the launchpads except LC-39. If this spot gets too popular I suspect they will again restrict it to employees only so I will not recommend it but you can check their facebook for more.
Note: You may hear some conflicting information from previous attendees about Port Canaveral being the best public location. The spot that they're referring to (the bleachers on route 401) was closed to the public in 2023 due to traffic concerns.
Your best option is Orlando International Airport. Melbourne Airport is closer but flights there are limited and often more expensive.
Rental car is easiest since there is no direct public transport to the center. From Orlando International Airport expect a roughly 60-75 minute drive, depending on traffic.
Private shuttle companies run direct round-trip services to the center for approximately $90, or you can take a public bus to Cocoa Beach and an uber or taxi the rest of the way.
Nearby hotels in Cape Canaveral or Cocoa Beach.
Paid parking available on-site, including for RVs.