• phase of project is expected to take 300 hours based on the fee
• only one person is scheduled / able to work on the project phase 50% of the time
• adding one fresh grad to assist you with the work will not enable said phase to be completed in 3 weeks. 

It's probably not a good idea to go after a project when:

• The client is known for only caring about the cost 
• The client doesn't actually know much about the building type
• The clients owners rep doesn't actually know much about the building type
• The owners rep doesn't understand that doing design build with a guaranteed maximum price doesn't actually save the owner any money
• The owners rep is vague to the point of dishonesty 

Good topic even though the OP provided more of complains rather than actual pro tips.  Venting is fine, but it's also good to brainstorm together how we can improve the project management at our workplace.  Here are some of my suggestions.

• Clear Work Plan Management on both sides - PM should create a work plan mapping out the work hours for each team members for next 3-4 weeks.  Then, PM to go over the work plans on a recurring weekly call with the team members to set the expectation.  On the flip site, team members need to review the work plan and provide feedbacks to the PM on weekly basis.  They cannot just wait for the half of the week and suddenly there are too much work for them.  It takes two to Tango and two way communications can avoid working 60 hours a week.   If a PM originally assigned 20 hours on a given week and suddenly ask you to do 60 hours in the middle of the week, then you can definitely push back for not doing his job on planning and execution.   I believe there are two sides to every story.
• Pay attention to SOW and Fee Proposals.  Both PMs and team members review carefully what they are selling on a proposal - Scope, Resources, Schedule, etc.  Once the proposal is accepted by the client, then the project resource is pretty much set.  You cannot come back later saying that you need another 200 hours, unless there is a legitimate ground for a CO.  If scope is unclear or complicated with the existing building conditions, then make sure to add disclaimers in the proposal, so you can cover yourself.  Lack of As-built drawings can be a good reason that you can push back on a client and ask for more hours.   

• Be upfront about your weekly workload - If you run into issues and problems meeting the timeline, Be proactive and bring it up to the PM or line managers at the beginning of the week.  This is one reason why a weekly team call is very important to forecast any workload and potential bottle necks.  Sometimes firms have multiple deadlines in a week.  Team members can use that time for their advantages too.  Give a PM the maximum time and availability per given week and anything more than that will need to be picked up a week after.  Draw a line in the sand early on, so that you wouldn't get ambushed by additional works.  I went back many time to my supervisors that I have competing priorities and ask them to help me what to focus on.  This sometimes led to PMs fight with each other for my time, but in the end, it helps me to sort out the workload on that week. 

Another pro tip for PMs:

- One of your basic responsibilities is to be the essential "membrane" between the client and the design team. Your job is to take client's demands, evaluate them against the time/capability of your team and THEN lay it upon your team. The "you heard what the client wants" excuse is lame and stupid.