When I used Illuminated Cloud (IC), I could deploy the metadata in the workspace to another org by selecting the Deploy All Metadata option from the context menu and select a different org to deploy to from within the IC dialog. How would I do this with the Salesforce Extension for VS Code? Both orgs in question are Trialforce orgs, not Sandbox, QA, Prod orgs.
You can deploy to any org using the terminal:
sfdx force:source:deploy -p force-app/ -u username-or-alias
Or you can set the default username (View > Command Palette... > SFDX: Set a Default Org) and then right-click on the file/folder to deploy and choose SFDX: Deploy Source to Org.