Friends - Our dreams are full of symbolism with their messengers being all different types of people. It is very common to dream about our friends. These are individuals that are emotionally valuable to us, and we learn about ourselves through them.
This dream is more than likely attempting to bring up uncomfortable feelings that you have about yourself, others...or more specifically, your relationship with your friends. (Remember "uncomfortable" does not necessarily mean bad).

Treehouse:
House - A house usually always represents you, or rather 'the self'...your body and the attributes of your personality.
They symbolize our emotional and psychological selves. All of your experiences, stages of development, and parts of your conscious and unconscious life may be represented by that house. The house may be representing issues concerning a particular dilemma in your life, or it may be more general and comprehensive.

The tree in your dream is you. The health, size and overall quality of the tree is indicative of how you feel about yourself. Lush green trees, symbolize new hopes, growth, desires, strength, and stability. You are concentrating on your own self-development and individuation. Also, consider whether the tree is alive with leaves, flowers or fruit, or if it's barren.

Bus:
Vehicle - usually symbolizes our passage through the journey of life. The way that you travel through your life's journey, and your effectiveness in controlling your life.
The type of vehicle will give indications of the type of experience being related in the dream message.

Bus - represents experiences, undertakings or relationships with groups of people, direction taken in company with others, trying to get somewhere but depending on others, and also problems pertaining to being overweight.
Stopping the bus and getting off would suggest you feel the need to stop being dependent on others. That you may want to 'break away' from group thinking, and do things on your own. If you are overweight, it could suggest that you want to change, or lose weight.

Chased - In this dreams like this, you are usually being chased by some villains, monsters, or unknown people who wish to harm you. But often these pursuers represent current tensions, or issues. This dream usually shows the level of stress you have at the moment, and is a signal to take control over the worries and resolve issues with a clear head. Alternately, you might be trying to avoid something. Identifying what, or who, the chaser represents might clarify what you're trying to avoid.  If the person or thing chasing you is identifiable as a part of yourself, the dream might involve a fear from within, such as an unhealthy relationship or unhealthy behavior.

What/who was chasing you? Does it remind you of someone, or something, in your waking life? It could be a responsibility, decision, problem, habit, of some kind. That it keeps getting bigger suggests that whatever it represents, is getting out of hand, or becoming uncontrollable.

Getting caught - represents guilt, or the feeling you're doing something you shouldn't be. Could also suggest you are being forced to see, or face, something you don't want to.

Museum - To dream of a museum, denotes you will pass through many and varied scenes in striving for what appears your rightful position. You will acquire useful knowledge, which will stand you in better light than if you had pursued the usual course to learning. If the museum is distasteful, you will have many causes for vexation.
Alternatively, the museum may represent a history of yourself and your past.
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Is there something that you need to do, but you don't want to?
Could you be running away from a problem that is getting out of hand?
Is there a decision you need to make, but you don't want to hurt others?
Is there a memory from your past that is re-entering into your current life?

Hope this helps, good luck!