Let's start here: "who builds 3 to 4 single family homes a year for homeowners with their own funds"
It's from the GC bank. It's always the GC funds.
"and I don't know how to go about keeping track of bills from the subcontractors or supply companies."
You need to understand your process. Example: You hire the subs, you submit proof of the Costs to pay, and the bank or title company pays the subs per your approvals, using the Homeowner's Construction Loan. This means your entry of the bills are handled as Other Current Asset, as Billable. Then, you invoice the title company along with the details. They send back proof they paid, and you enter this as Payment against the "reimbursement" invoice you created. The easiest way to do all of this is with a Bank type of account named "Construction Clearing." And everything you enter as spent, from that Bank type of account as Write Check, is done using a Single-sided Item linked to one CIP (construction in progress) Other Asset account. You enter the details on the Items tab as Billable to the customer project name. You invoice using the Add Time & Costs button, and this is what you send to the title company. This also Clears out the Other Asset account. You get the notice of total paid out, and you "receive" the payment against the invoice and "deposit" to that Clearing Bank. Now it is $0, in theory, as it just offset what you had entered you incurred (but never actually paid for, directly).
"I would like to enter them into QB, but most of them are being compensated from the Title company and the construction loan is the homeowner's, not the GC's. So I only enter my GC's direct expenses."
You can enter Both types of activities.
"With that there are a couple of issues I have:
*I lose track of whom I owe and how much, etc. especially when there are a few projects going on"
Always Job Track the split details on the Items tab of the checks.
"I don't have the idea of the current total expense, unless I add QB GC expenses and the title company pay outs manually, e.g. in excel which I have to update whenever there are new expenses,"
This is why you don't use the Expenses tab for the entries. Instead of a financial report (P&L), you want to run Job Reports. Job Cost reports can be filtered, for instance, on the CIP account only.
You want to use the Job Tracking and reporting tools, not rely on the Financial reports for this.