How to connect to only one remote PC from a home network?

Hi everyone,
I need to have access to a workstation via VLAN or/and VPN from my home network.
Here is the schematic:
mynet.png
I need to have access only to PC 1 in building B from building A. PC 1 is running Windows 7.

Site A is my home, I have a 3G connection via a USB modem and an x86-based computer running RouterOS 5.18. The remote IP is 10.43.43.117 and the local addresses are 192.168.1.0/24.

Site B is another house with 40-mbit internet via PPPoE and there is a rb751u-2hnd. I don’t currently know the firmware version, but it was bought a year ago. It has a real dynamic remote IP with no ports blocked by the provider. The local addresses are 192.168.88.0/24 and I have full control over the router.
All PCs in site B except PC 1 are not mine and I do not want to give them access to my home LAN.

Currently I am using TeamViewer. :frowning: If I had a real IP at home, I would have a DDNS name and start a L2TP server and connect to it with native Windows 7 services. But I have no such opportunity and that’s why I’m here.

I have an idea of starting a L2TP server in site B, connecting both the home router and PC 1 as clients and that’s it.
Any suggestions?
Thanks in advance.

It depends what you mean by “access”. e.g. - you could just port forward and run VNC which would give you one form of “access”.

I want multiple services(DLNA, Remote desktop, SMB file sharing and printing) and it would be great if PC 1 is visible as if it’s on my home network.