It seems as if you have a lot going on. I can offer some very general guidance since I do not know very much about your particular situation.
As for taking your child out of state - Washington law requires parents who intend to permanently move or relocate with a child to provide notice to the other parent. If the parents disagree about whether the child should move with the parent, then the judge will make that decision. Generally speaking, if there is no language in your current temporary order that limits you or your son's mother from traveling out of state, then vacations and trips out of state are fine.
Regarding your son - Washington uses different words than "joint custody" and "custodial rights". In Washington, the law assumes that both parents have custodial rights to their child. The question is how those rights are allocated. It sounds like your son's mother has "primary residential placement" of your son, and you have "secondary residential placement". These designations allocate each of your access rights to your child, but do not limit either of you from joint decision-making, access to medical or school records, or other important rights parents have with their children. This is what people mean when they say you have "joint custody".
Regarding your personal property - generally speaking, a temporary order that requires spouses to share 50/50 household furnishings is referring to household furnishings that you and your wife had in your house at the time you separated, not things that she has purchased after that date. If you are concerned that you are not receiving the household furnishings you are entitled to, you will have to bring this back to the court's attention by filing some kind of motion, the specifics of which I cannot speculate about since I do not have enough information to do so. I can say that it is probably best for you to have a list of specific items you want from the home. You may be able to ask the judge to allow you to take an inventory of the items in the home - under certain limited circumstances the judge may allow this to occur. I don't know if those circumstances exist in your case so you should consult with an attorney about this.
Finally - again, check with a Tacoma lawyer for more information about your specific situation, because it is possible for me to give you specific advice about your personal situation - your question does not provide me with enough information to do so.
Regarding your son and taking him out of the state without your permission: if your parenting plan, or temporary parenting plan require such permission before taking him out of the state, your ex-wife must seek your permission. You can not deny permission unreasonably, but she must still get your permission prior to the event, or you may have cause to file for contempt of court. In Washington State, some determinations of contempt of court can lead to loss of custody or other actions that the court deems are in the best interests of your child.
These types of permission requirements are normally binding on both parents, so you would have to get your ex-wife's permission before you take your son out of the state, as well. If this requirement is not in your parenting plan or temporary parenting plan, then it is unlikely that either of you needs prior permission to travel with your son outside the state.
Regarding the furnishings: if you do not believe you are getting the items you are entitled to, consult your family law attorney right away so you can schedule a time to go into the home with legal notice and accompanied (perhaps by a sheriff or other law enforcement officer) to identify what you are getting and take it right then.
In your case, waiting to take action is not advisable, it will only make your situation worse. The sooner you address these issues, resolve them, and put them behind you the sooner you can all start focussing on adapting to your new life situations.
Good luck, and don't forget to make your son's best interests the most important consideration in whatever course of action you decide.
Of course it depends on the language of any orders or Parenting Plan that is in place. Generally, either parent can take the kids wherever they want on their own time.
If the temporary orders say you get half, make an inventory of what was there and be prepared to prove what was there. Get an order from the court for you to be allowed to go to home and inventory and take pictures/video.