Since PS 5.0, I think there is now another cleaner way:
Utilise Copy-Item's ToSession parameter to copy the local module to the remote machine.
This doesn't involve the disadvantages of previous solutions:
- No need to copy the module to remote machines before hand
- No shared folders or re-creating the module dynamically:
Example usage:
$s = New-PSSession MyTargetMachine
Get-Module MyLocalModule | Import-LocalModuleToRemoteSession -Session $s -Force
# Show module is loaded
Invoke-Command $s -ScriptBlock { Get-Module }
Import-LocalModuleToRemoteSession function
Note it doesn't load the module dependencies
<#
    .SYNOPSIS
        Imports a loaded local module into a remote session
        
    .DESCRIPTION 
        This script copies a module's files loaded on the local machine to a remote session's temporary folder and imports it, before removing the temporary files.
                
        It does not require any shared folders to be exposed as it uses the default Copy-To -ToSession paramter (added in PS 5.0). 
#>
function Import-LocalModuleToRemoteSession
{
    [CmdletBinding()]
    param(
        # Module to import
        [Parameter(ValueFromPipeline,ValueFromPipelineByPropertyName,Mandatory)]
        [System.Management.Automation.PSModuleInfo]$ModuleInfo,
        # PSSession to import module to
        [Parameter(Mandatory)]
        [System.Management.Automation.Runspaces.PSSession]
        $Session,
        # Override temporary folder location for module to be copied to on remote machine 
        [string]
        $SessionModuleFolder=$null,
        [switch]
        $Force,
        [switch]
        $SkipDeleteModuleAfterImport
    )
    begin{
        function New-TemporaryDirectory {
            $parent = [System.IO.Path]::GetTempPath()
            [string] $name = [System.Guid]::NewGuid()
            New-Item -ItemType Directory -Path (Join-Path $parent $name)
        }
    }
    process{
        
        if( [string]::IsNullOrWhiteSpace($SessionModuleFolder) ){
            Write-Verbose "Creating temporary module folder"
            $item = Invoke-Command -Session $Session -ScriptBlock ${function:New-TemporaryDirectory} -ErrorAction Stop
            $SessionModuleFolder = $item.FullName
            Write-Verbose "Created temporary folder $SessionModuleFolder"
        }
        $directory = (Join-Path -Path $SessionModuleFolder -ChildPath $ModuleInfo.Name)
        Write-Verbose "Copying module $($ModuleInfo.Name) to remote folder: $directory"
        Copy-Item `
            -ToSession $Session `
            -Recurse `
            -Path $ModuleInfo.ModuleBase `
            -Destination $directory
        
        Write-Verbose "Importing module on remote session @ $directory "
        try{
            Invoke-Command -Session $Session -ErrorAction Stop -ScriptBlock `
            { 
                Get-ChildItem (Join-Path -Path ${Using:directory} -ChildPath "*.psd1") `
                    | ForEach-Object{ 
                        Write-Debug "Importing module $_"
                        Import-Module -Name $_ #-Force:${Using:Force}
                    }
                
                    if( -not ${Using:SkipDeleteModuleAfterImport} ){
                        Write-Debug "Deleting temporary module files: $(${Using:directory})"
                        Remove-Item -Force -Recurse ${Using:directory}
                    }
            }
        }
        catch
        {
            Write-Error "Failed to import module on $Session with error: $_"
        }
    }
}