The context is quite helpful here.
It seems that the wife is rather bothered with how her husband is currently passing his days. When she says,
She's expressing frustration that all he does is watch TV. So, person A asks,
Isn't that OK? Up until now, he worked for 40 years?
The wife demurs with でも、・・・ to which person A then asks,
Is it that you want your husband to work some more?
The grammar here is that of "wanting someone else to do something". In this situation, the verb is then used in the て-form followed by ほしい to express the idea of "want [someone] to do [something]". The person wanting this is the subject of the sentence and would likely be marked by が/は depending on context. The someone who is wanted to do something is usually going to be marked by に, the particle to show the agent of the action.
Back to the story...
So, the wife then responds,
No [I don't want him to go back to work]. For the sake of his health, it'd just be nice if he'd go out once in a while.
First let's look at 出かけてくれたら here. She'd like her husband to do something other than sit and watch TV, so going out once in a while would be a kind of favor to her. Hence the use of てくれる here.
Second let's look at 少しは. Here I wouldn't consider は to be a topic marker at all. Nor would I consider it contrastive (but someone might be able to argue that point). I'd say that it adds emphasis which is why in my translation I used the word "just". There are certainly other ways to translate 少し instead of temporally as I did; I could have written "If he'd just go out a little bit" might be a bit more faithful to the Japanese.
At any rate, I hope this helps clarify your two points.