Unfortunately I don't know anything about the Toronto area but in general, crime is higher in the West period not just in Surrey, that's just statistics. So even Vancouver, Edmonton, Calgary, Regina, etc., all have noticeably higher crime statistics compared to the Toronto area. Why? I don't know that's just how it is right now. So I can't comment as to comparing it to any area in the Toronto area unfortunately. I know Scarborough's reputation but those that have seen me post on these forums also know I try really hard not to jump to conclusions based on "reputation" alone. For all I know it could be a context thing and Scarborough could be "horrible" in the Toronto area but stacked against other regions in Canada, could be glowing.
As a native Surrey resident though, there are a few things with respect to avoiding crime in Surrey. First, don't join a gang. A large chunk of our crime in the violent category is directly gang related, and many of it is gangsters against gangsters so your average Joe is at little to no real risk.
The second is definitely pick the right area. Realistically you can't paint Surrey with a single brush (though some try). Crime rates in South Surrey for example are lower than most other neighborhoods in Greater Vancouver whereas crime rates in some other parts like Whalley and parts of Newton are higher.
It varies. Also the types of crime vary. If you aren't going to have a car and you have no furniture or really any possessions than you're really not at risk of auto theft (a big number in Surrey) or property crime (a big number in many parts of Metro Vancouver period). Context.
Guildford specifically I would personally avoid anything between 152nd and 140th East/West, and 104th and 110th North/South. Especially the area just North of Guildford Mall itself around 150th and 104th to 108th. That area is fairly low income so you're likelihood of brushing with criminal elements is higher.
It comes down to how far you are willing to commute. Your best bet is to try and find something in either the Fleetwood area or around Surrey Central/King George Station apartment (highrise) wise. Something newer. You will pay more than $500 though. You could also look at any area along 152nd basically from 104th South. Bus service is fine along that major road and income levels are generally middle to high along that stretch.
Another though again if you're ok with commuting is to look across the water into New Westminster or even towards Lougheed. You can take SkyTrain and then the B-Line to Guildford. If you definitely want to stay right in Guildford though then I'd look South or East or Guildford Mall as the developments there are a bit newer.
Or look towards Fraser Highway and 148th near Green Timbers. Places around there are olders but they are fairly established neighborhoods that have no less or more crime than any other neighborhood in the region.
Surrey has some hot spots but the majority of it isn't full of crime at every corner turn.
Your best bet actually would be to find several areas you're looking at and maybe post them here in this thread so those of us familiar with Surrey can give you a native's perspective.